Class 10 Maths Chapter 5 Exercise 5.2 Solutions in Assamese | SEBA Class 10 Maths New Book

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āĻ…āϧ্āϝাāϝ় āĻ…āϧ্āϝাāϝ় ā§Ģ: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি
āĻ…āύুāĻļীāϞāύী 5.2

āĻ…āϧ্āϝাāϝ় ā§Ģ : āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি — āĻ…āύুāĻļীāϞāύী 5.2 (Exercise 5.2 Solutions)

💡 āĻŽূāϞ āϏূāϤ্ā§°:
• āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° n-āϤāĻŽ āĻĒāĻĻ: an = a + (n - 1)d

āĻĒ্ā§°āĻļ্āύ ā§§: āĻĻিāϝ়া āφāĻ›ে āϝে āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ a, āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ d āφ⧰ু n-āϤāĻŽ āĻĒāĻĻ an। āϤāϞ⧰ āϤাāϞিāĻ•াāĻ–āύ⧰ āĻ–াāϞী āĻ াāχāϏāĻŽূāĻš āĻĒূā§°āĻŖ āϕ⧰া :

(i) a = 7, d = 3, n = 8, an = ?
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 7
āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = 3
āĻĒāĻĻā§° āϏংāĻ–্āϝা (n) = 8

āφāĻŽি āϜাāύো āϝে, āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° n-āϤāĻŽ āĻĒāĻĻā§° āϏূāϤ্ā§°—
an = a + (n - 1)d
āĻŽাāύāϏāĻŽূāĻš āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ,
⇒ a8 = 7 + (8 - 1) × 3
⇒ a8 = 7 + (7) × 3
⇒ a8 = 7 + 21
⇒ a8 = 28
āĻ—āϤিāĻ•ে, āύিā§°্āĻŖেāϝ় an = 28।


(ii) a = -18, d = ?, n = 10, an = 0
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
a = -18
n = 10
an = 0

āϏূāϤ্ā§°āĻŽāϤে,
an = a + (n - 1)d
⇒ 0 = -18 + (10 - 1)d
⇒ 0 = -18 + 9d
⇒ 9d = 18
⇒ d = 18 / 9
⇒ d = 2
āĻ—āϤিāĻ•ে, āύিā§°্āĻŖেāϝ় āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = 2।


(iii) a = ?, d = -3, n = 18, an = -5
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
d = -3
n = 18
an = -5

āϏূāϤ্ā§°āĻŽāϤে,
an = a + (n - 1)d
⇒ -5 = a + (18 - 1)(-3)
⇒ -5 = a + (17)(-3)
⇒ -5 = a - 51
⇒ a = -5 + 51
⇒ a = 46
āĻ—āϤিāĻ•ে, āύিā§°্āĻŖেāϝ় āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 46।


(iv) a = -18.9, d = 2.5, n = ?, an = 3.6
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
a = -18.9
d = 2.5
an = 3.6

āϏূāϤ্ā§°āĻŽāϤে,
an = a + (n - 1)d
⇒ 3.6 = -18.9 + (n - 1)2.5
⇒ 3.6 + 18.9 = (n - 1)2.5
⇒ 22.5 = (n - 1)2.5
⇒ (n - 1) = 22.5 / 2.5
⇒ n - 1 = 9
⇒ n = 9 + 1
⇒ n = 10
āĻ—āϤিāĻ•ে, āύিā§°্āĻŖেāϝ় āĻĒāĻĻā§° āϏংāĻ–্āϝা (n) = 10।


(v) a = 3.5, d = 0, n = 105, an = ?
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
a = 3.5
d = 0
n = 105

āϏূāϤ্ā§°āĻŽāϤে,
an = a + (n - 1)d
⇒ a105 = 3.5 + (105 - 1) × 0
⇒ a105 = 3.5 + 104 × 0
⇒ a105 = 3.5 + 0
⇒ a105 = 3.5
āĻ—āϤিāĻ•ে, āύিā§°্āĻŖেāϝ় an = 3.5।

āĻĒ্ā§°āĻļ্āύ ⧍: āϤāϞ⧰ āĻĒ্ā§°āϤিāϟোā§°ে āĻļুāĻĻ্āϧ āωāϤ্āϤ⧰āϟো āĻŦাāĻ›ি āωāϞিāĻ“ā§ąা āφ⧰ু āĻ•াā§°āĻŖ āĻĻā§°্āĻļোā§ąা :

(i) 10, 7, 4, ... āĻāχ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° 30āϤāĻŽ āĻĒāĻĻāϟো—
(A) 97
(B) 77
(C) -77
(D) -87

āϏāĻŽাāϧাāύ āφ⧰ু āĻ•াā§°āĻŖ:
āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো: 10, 7, 4, ...
āχāϝ়াāϤ,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 10
āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = 7 - 10 = -3
āĻĒāĻĻā§° āϏংāĻ–্āϝা (n) = 30

āφāĻŽি āϜাāύো āϝে,
an = a + (n - 1)d
⇒ a30 = 10 + (30 - 1)(-3)
⇒ a30 = 10 + (29)(-3)
⇒ a30 = 10 - 87
⇒ a30 = -77
āωāϤ্āϤ⧰: (C) -77


(ii) -3, -1/2, 2, ... āĻāχ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° 11āϤāĻŽ āĻĒāĻĻāϟো—
(A) 28
(B) 22
(C) -38
(D) -48(1/2)

āϏāĻŽাāϧাāύ āφ⧰ু āĻ•াā§°āĻŖ:
āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো: -3, -1/2, 2, ...
āχāϝ়াāϤ,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = -3
āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = -1/2 - (-3) = -1/2 + 3 = (-1 + 6) / 2 = 5/2
āĻĒāĻĻā§° āϏংāĻ–্āϝা (n) = 11

āφāĻŽি āϜাāύো āϝে,
an = a + (n - 1)d
⇒ a11 = -3 + (11 - 1)(5/2)
⇒ a11 = -3 + (10)(5/2)
⇒ a11 = -3 + 5 × 5
⇒ a11 = -3 + 25
⇒ a11 = 22
āωāϤ্āϤ⧰: (B) 22

āĻĒ্ā§°āĻļ্āύ ā§Š: āϤāϞ⧰ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϏāĻŽূāĻšā§° āĻ–াāϞীāϘ⧰ āĻ•েāχāϟাā§° āϞুāĻĒ্āϤ āĻĒāĻĻāϏāĻŽূāĻš (missing terms) āύিā§°্āĻŖāϝ় āϕ⧰া :

(i) 2, [ ], 26
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 2
āϤৃāϤীāϝ় āĻĒāĻĻ (a3) = 26

āφāĻŽি āϜাāύো āϝে, a3 = a + 2d
⇒ 26 = 2 + 2d
⇒ 26 - 2 = 2d
⇒ 2d = 24
⇒ d = 24 / 2
⇒ d = 12

āĻ…āϤāĻāĻŦ, āϞুāĻĒ্āϤ āĻĻ্āĻŦিāϤীāϝ় āĻĒāĻĻ (a2) = a + d
⇒ a2 = 2 + 12 = 14
āωāϤ্āϤ⧰: 14


(ii) [ ], 13, [ ], 3
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
āĻĻ্āĻŦিāϤীāϝ় āĻĒāĻĻ (a2) = 13 ⇒ a + d = 13 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)
āϚāϤুā§°্āĻĨ āĻĒāĻĻ (a4) = 3 ⇒ a + 3d = 3 -------- (āϏāĻŽীāϕ⧰āĻŖ ⧍)

āϏāĻŽীāϕ⧰āĻŖ (⧍) ā§° āĻĒā§°া (ā§§) āĻŦিāϝ়োāĻ— āϕ⧰ি āĻĒাāĻ“ঁ:
(a + 3d) - (a + d) = 3 - 13
⇒ 2d = -10
⇒ d = -10 / 2
⇒ d = -5

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + (-5) = 13
⇒ a = 13 + 5
⇒ a = 18 (āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ)

āϤৃāϤীāϝ় āĻĒāĻĻ (a3) = a + 2d
⇒ a3 = 18 + 2(-5)
⇒ a3 = 18 - 10 = 8
āωāϤ্āϤ⧰: āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ = 18, āϤৃāϤীāϝ় āĻĒāĻĻ = 8


(iii) 5, [ ], [ ], 9(1/2)
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 5
āϚāϤুā§°্āĻĨ āĻĒāĻĻ (a4) = 9(1/2) = 19/2

āφāĻŽি āϜাāύো āϝে, a4 = a + 3d
⇒ 19/2 = 5 + 3d
⇒ 19/2 - 5 = 3d
⇒ (19 - 10) / 2 = 3d
⇒ 9/2 = 3d
⇒ d = 9 / (2 × 3)
⇒ d = 3/2

āĻĻ্āĻŦিāϤীāϝ় āĻĒāĻĻ (a2) = a + d = 5 + 3/2 = (10 + 3) / 2 = 13/2 = 6(1/2)
āϤৃāϤীāϝ় āĻĒāĻĻ (a3) = a2 + d = 13/2 + 3/2 = 16/2 = 8
āωāϤ্āϤ⧰: āĻĻ্āĻŦিāϤীāϝ় āĻĒāĻĻ = 6(1/2), āϤৃāϤীāϝ় āĻĒāĻĻ = 8


(iv) -4, [ ], [ ], [ ], [ ], 6
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = -4
āώāώ্āĻ  āĻĒāĻĻ (a6) = 6

a6 = a + 5d
⇒ 6 = -4 + 5d
⇒ 6 + 4 = 5d
⇒ 10 = 5d
⇒ d = 2

a2 = a + d = -4 + 2 = -2
a3 = a2 + d = -2 + 2 = 0
a4 = a3 + d = 0 + 2 = 2
a5 = a4 + d = 2 + 2 = 4
āωāϤ্āϤ⧰: -2, 0, 2, 4


(v) [ ], 38, [ ], [ ], [ ], -22
āϏāĻŽাāϧাāύ:
a2 = 38 ⇒ a + d = 38 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)
a6 = -22 ⇒ a + 5d = -22 -------- (āϏāĻŽীāϕ⧰āĻŖ ⧍)

āϏāĻŽীāϕ⧰āĻŖ (⧍) ā§° āĻĒā§°া (ā§§) āĻŦিāϝ়োāĻ— āϕ⧰ি āĻĒাāĻ“ঁ:
(a + 5d) - (a + d) = -22 - 38
⇒ 4d = -60
⇒ d = -15

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + (-15) = 38
⇒ a = 38 + 15 = 53 (āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ)

a3 = a2 + d = 38 + (-15) = 23
a4 = a3 + d = 23 + (-15) = 8
a5 = a4 + d = 8 + (-15) = -7
āωāϤ্āϤ⧰: 53, 23, 8, -7

āĻĒ্ā§°āĻļ্āύ ā§Ē - ā§§ā§Ļ: āĻ—াāĻŖিāϤিāĻ• āϏāĻŽাāϧাāύāϏāĻŽূāĻš :

āĻĒ্ā§°āĻļ্āύ ā§Ē: 3, 8, 13, 18, ... āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āĻ•োāύāϟো āĻĒāĻĻ 78?
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো: 3, 8, 13, 18, ...
āχāϝ়াāϤ,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 3
āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = 8 - 3 = 5
āϧ⧰ো, n-āϤāĻŽ āĻĒāĻĻ (an) = 78

āφāĻŽি āϜাāύো āϝে, an = a + (n - 1)d
⇒ 78 = 3 + (n - 1)5
⇒ 78 - 3 = 5(n - 1)
⇒ 75 = 5(n - 1)
⇒ n - 1 = 75 / 5
⇒ n - 1 = 15
⇒ n = 15 + 1
⇒ n = 16
āωāϤ্āϤ⧰: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° 16āϤāĻŽ āĻĒāĻĻāϟো 78।


āĻĒ্ā§°āĻļ্āύ ā§Ģ: āϤāϞ⧰ āĻĒ্ā§°āϤিāϟো āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āĻĒāĻĻā§° āϏংāĻ–্āϝা āύিā§°্āĻŖāϝ় āϕ⧰া :
(i) 7, 13, 19, ..., 205
āϏāĻŽাāϧাāύ:
a = 7
d = 13 - 7 = 6
n-āϤāĻŽ āĻĒāĻĻ (an) = 205

an = a + (n - 1)d
⇒ 205 = 7 + (n - 1)6
⇒ 205 - 7 = 6(n - 1)
⇒ 198 = 6(n - 1)
⇒ n - 1 = 198 / 6
⇒ n - 1 = 33
⇒ n = 34
āωāϤ্āϤ⧰: āĻĒāĻĻā§° āϏংāĻ–্āϝা = 34

(ii) 18, 15(1/2), 13, ..., -47
āϏāĻŽাāϧাāύ:
a = 18
d = 15(1/2) - 18 = 31/2 - 18 = (31 - 36) / 2 = -5/2
an = -47

an = a + (n - 1)d
⇒ -47 = 18 + (n - 1)(-5/2)
⇒ -47 - 18 = (n - 1)(-5/2)
⇒ -65 = (n - 1)(-5/2)
⇒ n - 1 = (-65 × 2) / (-5)
⇒ n - 1 = 13 × 2
⇒ n - 1 = 26
⇒ n = 27
āωāϤ্āϤ⧰: āĻĒāĻĻā§° āϏংāĻ–্āϝা = 27


āĻĒ্ā§°āĻļ্āύ ā§Ŧ: 11, 8, 5, 2 ..... āĻāχ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° -150 āϏংāĻ–্āϝাāϟো āĻ•োāύো āĻāϟা āĻĒāĻĻ āĻš'āĻŦ āĻĒাā§°েāύে āĻĒā§°ীāĻ•্āώা āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো: 11, 8, 5, 2, ...
a = 11
d = 8 - 11 = -3
āϧ⧰ো, n-āϤāĻŽ āĻĒāĻĻ (an) = -150

an = a + (n - 1)d
⇒ -150 = 11 + (n - 1)(-3)
⇒ -150 - 11 = -3(n - 1)
⇒ -161 = -3(n - 1)
⇒ n - 1 = 161 / 3
⇒ n = 161/3 + 1
⇒ n = (161 + 3) / 3
⇒ n = 164 / 3

āϝিāĻšেāϤু n ā§° āĻŽাāύ āĻāϟা āϧāύাāϤ্āĻŽāĻ• āĻ…āĻ–āĻŖ্āĻĄ āϏংāĻ–্āϝা āĻš'āĻŦ āϞাāĻ—ে āĻ•িāύ্āϤু āχāϝ়াāϤ 164/3 āĻāϟা āĻ­āĻ—্āύাংāĻļ,
āωāϤ্āϤ⧰: -150 āϏংāĻ–্āϝাāϟো āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āĻ•োāύো āĻĒāĻĻ āĻš'āĻŦ āύোā§ąাā§°ে।


āĻĒ্ā§°āĻļ্āύ ā§­: āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° 11āϤāĻŽ āĻĒāĻĻāϟো 38 āφ⧰ু 16āϤāĻŽ āĻĒāĻĻāϟো 73 āĻš'āϞে āϤাā§° 31āϤāĻŽ āĻĒāĻĻāϟো āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
a11 = 38 ⇒ a + 10d = 38 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)
a16 = 73 ⇒ a + 15d = 73 -------- (āϏāĻŽীāϕ⧰āĻŖ ⧍)

āϏāĻŽীāϕ⧰āĻŖ (⧍) ā§° āĻĒā§°া (ā§§) āĻŦিāϝ়োāĻ— āϕ⧰ি āĻĒাāĻ“ঁ:
(a + 15d) - (a + 10d) = 73 - 38
⇒ 5d = 35
⇒ d = 35 / 5
⇒ d = 7

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + 10(7) = 38
⇒ a + 70 = 38
⇒ a = 38 - 70
⇒ a = -32

āĻāϤিāϝ়া, 31āϤāĻŽ āĻĒāĻĻ (a31) āύিā§°্āĻŖāϝ় āϕ⧰োঁ:
a31 = a + 30d
⇒ a31 = -32 + 30(7)
⇒ a31 = -32 + 210
⇒ a31 = 178
āωāϤ্āϤ⧰: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° 31āϤāĻŽ āĻĒāĻĻāϟো 178।


āĻĒ্ā§°āĻļ্āύ ā§Ž: āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϤ 50 āϟা āĻĒāĻĻ āφāĻ›ে āϝাā§° āϤৃāϤীāϝ় āĻĒāĻĻāϟো 12 āφ⧰ু āĻļেāώ āĻĒāĻĻāϟো 106। 29āϤāĻŽ āĻĒāĻĻāϟো āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
āĻŽুāĻ  āĻĒāĻĻā§° āϏংāĻ–্āϝা (n) = 50
āϤৃāϤীāϝ় āĻĒāĻĻ (a3) = 12 ⇒ a + 2d = 12 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)
āĻļেāώ āĻĒāĻĻ (a50) = 106 ⇒ a + 49d = 106 -------- (āϏāĻŽীāϕ⧰āĻŖ ⧍)

āϏāĻŽীāϕ⧰āĻŖ (⧍) ā§° āĻĒā§°া (ā§§) āĻŦিāϝ়োāĻ— āϕ⧰ি āĻĒাāĻ“ঁ:
47d = 94
⇒ d = 94 / 47
⇒ d = 2

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + 2(2) = 12
⇒ a + 4 = 12
⇒ a = 8

āĻāϤিāϝ়া, 29āϤāĻŽ āĻĒāĻĻ (a29) āύিā§°্āĻŖāϝ় āϕ⧰োঁ:
a29 = a + 28d
⇒ a29 = 8 + 28(2)
⇒ a29 = 8 + 56
⇒ a29 = 64
āωāϤ্āϤ⧰: 29āϤāĻŽ āĻĒāĻĻāϟো 64।


āĻĒ্ā§°āĻļ্āύ ⧝: āϝāĻĻি āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āϤৃāϤীāϝ় āφ⧰ু āĻ¨ā§ąāĻŽ āĻĒāĻĻ āĻĻুāϟা āĻ•্ā§°āĻŽে 4 āφ⧰ু -8 āĻšāϝ় āϤেāύ্āϤে āχāϝ়াā§° āĻ•োāύāϟো āĻĒāĻĻ āĻļূāύ্āϝ āĻš'āĻŦ?
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
a3 = 4 ⇒ a + 2d = 4 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)
a9 = -8 ⇒ a + 8d = -8 -------- (āϏāĻŽীāϕ⧰āĻŖ ⧍)

āϏāĻŽীāϕ⧰āĻŖ (⧍) ā§° āĻĒā§°া (ā§§) āĻŦিāϝ়োāĻ— āϕ⧰ি āĻĒাāĻ“ঁ:
6d = -12
⇒ d = -12 / 6
⇒ d = -2

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + 2(-2) = 4
⇒ a - 4 = 4
⇒ a = 8

āϧ⧰ো, n-āϤāĻŽ āĻĒāĻĻ (an) = 0
a + (n - 1)d = 0
⇒ 8 + (n - 1)(-2) = 0
⇒ -2(n - 1) = -8
⇒ n - 1 = -8 / -2
⇒ n - 1 = 4
⇒ n = 5
āωāϤ্āϤ⧰: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° 5āĻŽ (āĻĒāĻž্āϚāĻŽ) āĻĒāĻĻāϟো āĻļূāύ্āϝ āĻš'āĻŦ।


āĻĒ্ā§°āĻļ্āύ ā§§ā§Ļ: āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° 17āϤāĻŽ āĻĒāĻĻāϟো 10āϤāĻŽ āĻĒāĻĻāϟোāϤāĻ•ৈ 7 āĻĄাāϙ⧰। āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĒ্ā§°āĻļ্āύāĻŽāϤে,
a17 - a10 = 7
⇒ (a + 16d) - (a + 9d) = 7
⇒ a + 16d - a - 9d = 7
⇒ 7d = 7
⇒ d = 7 / 7
⇒ d = 1
āωāϤ্āϤ⧰: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ d = 1।

āĻĒ্ā§°āĻļ্āύ ā§§ā§§ - ⧍ā§Ģ: āϞিāĻ–িāϤ āφ⧰ু āĻŦāĻšু-āĻŦিāĻ•āϞ্āĻĒāĻ­িāϤ্āϤিāĻ• (MCQs) āĻĒ্ā§°āĻļ্āύāϏāĻŽূāĻš :

āĻĒ্ā§°āĻļ্āύ ā§§ā§§: 3, 15, 27, 39, ... āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āĻ•োāύāϟো āĻĒāĻĻ 54āϤāĻŽ āĻĒāĻĻāϤāĻ•ৈ 132 āĻĄাāϙ⧰?
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো: 3, 15, 27, 39, ...
a = 3, d = 15 - 3 = 12

āĻĒ্ā§°āĻĨāĻŽে 54āϤāĻŽ āĻĒāĻĻ (a54) āωāϞিāϝ়াāĻ“ঁ:
a54 = a + 53d
⇒ a54 = 3 + 53(12)
⇒ a54 = 3 + 636 = 639

āĻĒ্ā§°āĻļ্āύāĻŽāϤে, āύিā§°্āĻŖেāϝ় n-āϤāĻŽ āĻĒāĻĻ (an) = a54 + 132
⇒ an = 639 + 132 = 771
⇒ a + (n - 1)d = 771
⇒ 3 + (n - 1)12 = 771
⇒ 12(n - 1) = 771 - 3
⇒ 12(n - 1) = 768
⇒ n - 1 = 768 / 12
⇒ n - 1 = 64
⇒ n = 65
āωāϤ্āϤ⧰: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° 65āϤāĻŽ āĻĒāĻĻāϟো 54āϤāĻŽ āĻĒāĻĻāϤāĻ•ৈ 132 āĻĄাāϙ⧰।


āĻĒ্ā§°āĻļ্āύ ⧧⧍: āĻĻুāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ āĻāĻ•ে। āϏিāĻšঁāϤ⧰ 100āϤāĻŽ āĻĒāĻĻ āĻĻুāϟাā§° āĻĒাā§°্āĻĨāĻ•্āϝ 100। āϏিāĻšঁāϤ⧰ 1000āϤāĻŽ āĻĒāĻĻ āĻĻুāϟাā§° āĻĒাā§°্āĻĨāĻ•্āϝ āĻ•িāĻŽাāύ?
āϏāĻŽাāϧাāύ:
āϧ⧰ো āĻĒ্ā§°āĻĨāĻŽ AP ā§° āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ = A, āφ⧰ু āĻĻ্āĻŦিāϤীāϝ় AP ā§° āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ = a।
āĻĻুāϝ়োāϟা AP ā§° āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ = d।

āĻĒ্ā§°āĻĨāĻŽ AP ā§° 100āϤāĻŽ āĻĒāĻĻ = A + 99d
āĻĻ্āĻŦিāϤীāϝ় AP ā§° 100āϤāĻŽ āĻĒāĻĻ = a + 99d

āĻĒ্ā§°āĻļ্āύāĻŽāϤে,
(A + 99d) - (a + 99d) = 100
⇒ A - a = 100 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)

āĻāϤিāϝ়া, 1000āϤāĻŽ āĻĒāĻĻ āĻĻুāϟাā§° āĻĒাā§°্āĻĨāĻ•্āϝ:
(A + 999d) - (a + 999d) = A - a = 100 (āϏāĻŽীāϕ⧰āĻŖ ā§§ ā§° āĻĒā§°া)
āωāϤ্āϤ⧰: āϏিāĻšঁāϤ⧰ 1000āϤāĻŽ āĻĒāĻĻ āĻĻুāϟাā§° āĻĒাā§°্āĻĨāĻ•্āϝ 100 āĻš'āĻŦ।


āĻĒ্ā§°āĻļ্āύ ā§§ā§Š: āĻ•িāĻŽাāύāϟা āϤিāύি āĻ…ংāĻ•āϝুāĻ•্āϤ āϏংāĻ–্āϝা 7 ā§°ে āĻŦিāĻ­াāϜ্āϝ?
āϏāĻŽাāϧাāύ:
7 ā§°ে āĻŦিāĻ­াāϜ্āϝ āϤিāύি āĻ…ংāĻ•āϝুāĻ•্āϤ āϏংāĻ–্āϝাāϏāĻŽূāĻš āĻš'āϞ: 105, 112, 119, ..., 994
āχ āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি āĻ—āĻ āύ āϕ⧰ে āϝ'āϤ,
a = 105, d = 7, āφ⧰ু āĻļেāώ āĻĒāĻĻ (an) = 994

an = a + (n - 1)d
⇒ 994 = 105 + (n - 1)7
⇒ 994 - 105 = 7(n - 1)
⇒ 889 = 7(n - 1)
⇒ n - 1 = 889 / 7
⇒ n - 1 = 127
⇒ n = 128
āωāϤ্āϤ⧰: 7 ā§°ে āĻŦিāĻ­াāϜ্āϝ āϤিāύি āĻ…ংāĻ•āϝুāĻ•্āϤ āϏংāĻ–্āϝা 128 āϟা āφāĻ›ে।


āĻĒ্ā§°āĻļ্āύ ā§§ā§Ē: 10 āφ⧰ু 250 ā§° āĻŽাāϜāϤ 4 ā§° āĻ—ুāĻŖিāϤāĻ• āĻ•িāĻŽাāύāϟা āφāĻ›ে?
āϏāĻŽাāϧাāύ:
10 āφ⧰ু 250 ā§° āĻŽাāϜāϤ 4 ā§° āĻ—ুāĻŖিāϤāĻ•āϏāĻŽূāĻš āĻš'āϞ: 12, 16, 20, ..., 248
āχāϝ়াāϤ, a = 12, d = 4, āφ⧰ু an = 248

an = a + (n - 1)d
⇒ 248 = 12 + (n - 1)4
⇒ 248 - 12 = 4(n - 1)
⇒ 236 = 4(n - 1)
⇒ n - 1 = 236 / 4
⇒ n - 1 = 59
⇒ n = 60
āωāϤ্āϤ⧰: 4 ā§° āĻ—ুāĻŖিāϤāĻ• 60 āϟা āφāĻ›ে।


āĻĒ্ā§°āĻļ্āύ ā§§ā§Ģ: n ā§° āĻ•ি āĻŽাāύ⧰ āĻŦাāĻŦে 63, 65, 67, ... āφ⧰ু 3, 10, 17, ... āĻāχ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি āĻĻুāϟাā§° nāϤāĻŽ āĻĒāĻĻ āĻĻুāϟা āϏāĻŽাāύ?
āϏāĻŽাāϧাāύ:
āĻĒ্ā§°āĻĨāĻŽ AP: 63, 65, 67, ...
a = 63, d = 65 - 63 = 2
n-āϤāĻŽ āĻĒāĻĻ = 63 + (n - 1)2 = 63 + 2n - 2 = 61 + 2n

āĻĻ্āĻŦিāϤীāϝ় AP: 3, 10, 17, ...
A = 3, D = 10 - 3 = 7
n-āϤāĻŽ āĻĒāĻĻ = 3 + (n - 1)7 = 3 + 7n - 7 = 7n - 4

āĻĒ্ā§°āĻļ্āύāĻŽāϤে,
61 + 2n = 7n - 4
⇒ 61 + 4 = 7n - 2n
⇒ 65 = 5n
⇒ n = 65 / 5
⇒ n = 13
āωāϤ্āϤ⧰: n = 13 ā§° āĻŦাāĻŦে āĻĒāĻĻ āĻĻুāϟা āϏāĻŽাāύ āĻš'āĻŦ।


āĻĒ্ā§°āĻļ্āύ ā§§ā§Ŧ: āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āϤৃāϤীāϝ় āĻĒāĻĻāϟো 16 āφ⧰ু āϏāĻĒ্āϤāĻŽ āĻĒāĻĻāϟো āĻĒāĻž্āϚāĻŽ āĻĒāĻĻāϟোāϤāĻ•ৈ 12 āĻĄাāϙ⧰। āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āφāĻ›ে,
a3 = 16 ⇒ a + 2d = 16 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)
a7 = a5 + 12
⇒ (a + 6d) = (a + 4d) + 12
⇒ a + 6d - a - 4d = 12
⇒ 2d = 12
⇒ d = 6

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + 2(6) = 16
⇒ a + 12 = 16
⇒ a = 4

āĻ—āϤিāĻ•ে āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো āĻš'āĻŦ:
a, a + d, a + 2d, a + 3d, ...
⇒ 4, (4 + 6), (4 + 12), (4 + 18), ...
āωāϤ্āϤ⧰: āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো āĻš'āϞ 4, 10, 16, 22, ...


āĻĒ্ā§°āĻļ্āύ ā§§ā§­: 3, 8, 13, ..., 253 āĻāχ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āĻļেāώ⧰ āĻĢাāϞ⧰ āĻĒā§°া 20āϤāĻŽ āĻĒāĻĻāϟো āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĻিāϝ়া āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো: 3, 8, 13, ..., 253
āϝāĻĻি āφāĻŽি āĻĒ্ā§°āĻ—āϤিāϟো āĻ“āϞোāϟাāĻ•ৈ āϞিāĻ–োঁ, āϤেāύ্āϤে—
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 253
āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = 3 - 8 = -5
āĻĒāĻĻā§° āϏংāĻ–্āϝা (n) = 20

āĻāϤিāϝ়া āĻļেāώ⧰ āĻĒā§°া 20āϤāĻŽ āĻĒāĻĻ (āĻ…ā§°্āĻĨাā§Ž āĻ“āϞোāϟা āĻĒ্ā§°āĻ—āϤিāϟোā§° 20āϤāĻŽ āĻĒāĻĻ) āωāϞিāϝ়াāĻ“ঁ:
a20 = a + (20 - 1)d
⇒ a20 = 253 + (19)(-5)
⇒ a20 = 253 - 95
⇒ a20 = 158
āωāϤ্āϤ⧰: āĻļেāώ⧰ āĻĢাāϞ⧰ āĻĒā§°া 20āϤāĻŽ āĻĒāĻĻāϟো 158।


āĻĒ্ā§°āĻļ্āύ ā§§ā§Ž: āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āϚāϤুā§°্āĻĨ āφ⧰ু āĻ…āώ্āϟāĻŽ āĻĒāĻĻ āĻĻুāϟাā§° āϝোāĻ—āĻĢāϞ 24 āφ⧰ু āώāώ্āĻ  āφ⧰ু āĻĻāĻļāĻŽ āĻĒāĻĻ āĻĻুāϟাā§° āϝোāĻ—āĻĢāϞ 44। āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟোā§° āĻĒ্ā§°āĻĨāĻŽ āϤিāύিāϟা āĻĒāĻĻ āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĒ্ā§°āĻĨāĻŽ āϚ⧰্āϤāĻŽāϤে,
a4 + a8 = 24
⇒ (a + 3d) + (a + 7d) = 24
⇒ 2a + 10d = 24
⇒ a + 5d = 12 -------- (āϏāĻŽীāϕ⧰āĻŖ ā§§)

āĻĻ্āĻŦিāϤীāϝ় āϚ⧰্āϤāĻŽāϤে,
a6 + a10 = 44
⇒ (a + 5d) + (a + 9d) = 44
⇒ 2a + 14d = 44
⇒ a + 7d = 22 -------- (āϏāĻŽীāϕ⧰āĻŖ ⧍)

āϏāĻŽীāϕ⧰āĻŖ (⧍) ā§° āĻĒā§°া (ā§§) āĻŦিāϝ়োāĻ— āϕ⧰ি āĻĒাāĻ“ঁ:
(a + 7d) - (a + 5d) = 22 - 12
⇒ 2d = 10
⇒ d = 5

d ā§° āĻŽাāύ āϏāĻŽীāϕ⧰āĻŖ (ā§§) āϤ āĻŦāĻšুā§ąাāχ āĻĒাāĻ“ঁ:
a + 5(5) = 12
⇒ a + 25 = 12
⇒ a = 12 - 25 = -13

āĻĒ্ā§°āĻĨāĻŽ āϤিāύিāϟা āĻĒāĻĻ:
a1 = -13
a2 = -13 + 5 = -8
a3 = -8 + 5 = -3
āωāϤ্āϤ⧰: āĻĒ্ā§°āĻĨāĻŽ āϤিāύিāϟা āĻĒāĻĻ āĻ•্ā§°āĻŽে -13, -8 āφ⧰ু -3।


āĻĒ্ā§°āĻļ্āύ ⧧⧝: 1995 āϚāύāϤ āϚāύ্āĻĻāύাāχ 5000 āϟāĻ•া āĻŦāϛ⧰েāĻ•ীāϝ়া āĻĻā§°āĻŽāĻšাāϤ āϚাāϕ⧰ি āφ⧰āĻŽ্āĻ­ āϕ⧰িāϞে āφ⧰ু āĻĒ্ā§°āϤি āĻŦāϛ⧰ে 200 āϟāĻ•াāĻ•ৈ āĻŦৃāĻĻ্āϧি (Increment) āϞাāĻ­ āϕ⧰িāϞে। āĻ•োāύ āĻŦāϛ⧰āϤ āϤেāĻ“ঁā§° āĻĻā§°āĻŽāĻšা 7000 āϟāĻ•া āĻš'āĻŦ?
āϏāĻŽাāϧাāύ:
āĻĒ্ā§°āϤি āĻŦāϛ⧰⧰ āĻĻā§°āĻŽāĻšাāϏāĻŽূāĻšে āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি āĻ—āĻ āύ āϕ⧰ে: 5000, 5200, 5400, ..., 7000
āχāϝ়াāϤ,
a = 5000
d = 200
an = 7000

an = a + (n - 1)d
⇒ 7000 = 5000 + (n - 1)200
⇒ 7000 - 5000 = 200(n - 1)
⇒ 2000 = 200(n - 1)
⇒ n - 1 = 2000 / 200
⇒ n - 1 = 10
⇒ n = 11

āĻ…āϤāĻāĻŦ, 11āϤāĻŽ āĻŦāϛ⧰āϤ āϤেāĻ“ঁā§° āĻĻā§°āĻŽāĻšা 7000 āϟāĻ•া āĻš'āĻŦ।
āύিā§°্āĻŖেāϝ় āϚāύ = 1995 + (11 - 1) = 2005 āϚāύ।
āωāϤ্āϤ⧰: 2005 āϚāύāϤ āϤেāĻ“ঁā§° āĻĻā§°āĻŽāĻšা 7000 āϟāĻ•া āĻš'āĻŦ।


āĻĒ্ā§°āĻļ্āύ ⧍ā§Ļ: ā§°াāĻŽāϚ⧰āĻŖে āĻ•োāύো āĻāϟা āĻŦāϛ⧰⧰ āĻĒ্ā§°āĻĨāĻŽ āϏāĻĒ্āϤাāĻšāϤ 5 āϟāĻ•া āϏāĻž্āϚāϝ় āϕ⧰িāϞে āφ⧰ু āĻĒ্ā§°āϤি āϏāĻĒ্āϤাāĻšāϤ āϏāĻž্āϚāϝ়ā§° āϧāύ 1.75 āϟāĻ•াāĻ•ৈ āĻŦāĻĸ়াāχ āĻ—ৈ āĻĨাāĻ•িāϞ। n-āϤāĻŽ āϏāĻĒ্āϤাāĻšāϤ āϤেāĻ“ঁā§° āϏাāĻĒ্āϤাāĻšিāĻ• āϏāĻž্āϚāϝ়ā§° āĻĒā§°িāĻŽাāĻŖ 20.75 āϟāĻ•া āĻš'āϞে n ā§° āĻŽাāύ āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āĻĒ্ā§°āϤি āϏāĻĒ্āϤাāĻšā§° āϏāĻž্āϚāϝ়ā§° āĻĒā§°িāĻŽাāĻŖে āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি āĻ—āĻ āύ āϕ⧰ে āϝ'āϤ,
āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) = 5
āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) = 1.75
n-āϤāĻŽ āϏāĻĒ্āϤাāĻšā§° āϏāĻž্āϚāϝ় (an) = 20.75

an = a + (n - 1)d
⇒ 20.75 = 5 + (n - 1)1.75
⇒ 20.75 - 5 = 1.75(n - 1)
⇒ 15.75 = 1.75(n - 1)
⇒ n - 1 = 15.75 / 1.75
⇒ n - 1 = 1575 / 175
⇒ n - 1 = 9
⇒ n = 9 + 1
⇒ n = 10
āωāϤ্āϤ⧰: n ā§° āĻŽাāύ = 10।


āĻĒ্ā§°āĻļ্āύ ⧍⧧: āϏ্āϤāĻŽ্āĻ­ (I) ā§° āϞāĻ—āϤ āϏ্āϤāĻŽ্āĻ­ (II) āĻŽিāϞোā§ąা :
āϏ্āϤāĻŽ্āĻ­ (I):
P) 2, 4, 6, 8... AP āϟোā§° a5 āĻš'āĻŦ
Q) -1.2, -3.2, -5.2, -7.2... AP āϟোā§° āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ (d) āĻš'āĻŦ
R) 3, 6, 9, 12... AP āϟোā§° āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ (a) āĻš'āĻŦ
S) 0, -4, -8, -12... AP āϟোā§° a4 - a3 ā§° āĻŽাāύ āĻš'āĻŦ
āϏ্āϤāĻŽ্āĻ­ (II):
1) -2
2) -4
3) 10
4) 3

āϏāĻŽাāϧাāύ:
P) 2, 4, 6, 8... ā§° a5 = a + 4d = 2 + 4(2) = 10 (āĻŽাāύ ā§Š)
Q) -1.2, -3.2... ā§° d = -3.2 - (-1.2) = -2 (āĻŽাāύ ā§§)
R) 3, 6, 9... ā§° āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ a = 3 (āĻŽাāύ ā§Ē)
S) 0, -4, -8, -12... ā§° a4 - a3 = -12 - (-8) = -4 (āĻŽাāύ ⧍)
āωāϤ্āϤ⧰: (B) P→3, Q→1, R→4, S→2


āĻĒ্ā§°āĻļ্āύ ⧍⧍: āϤāϞāϤ āĻĻিāϝ়া āĻ•োāύāĻŦোā§° āωāĻ•্āϤি āĻļুāĻĻ্āϧ āĻŦা āĻ…āĻļুāĻĻ্āϧ?
P) a1, a2, a3... āĻāϟা AP āĻš'āĻŦ āϝāĻĻিāĻšে an+1 - an, n āϏাāĻĒেāĻ•্āώে āϏ্āĻŦāϤāύ্āϤ্ā§° āĻšāϝ় (āĻļুāĻĻ্āϧ)।
Q) a1, a2... AP āϟোā§° āĻŦাāĻŦে ap - aq = (p - q)d (āĻļুāĻĻ্āϧ)।
R) AP āϟোā§° āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ a āφ⧰ু āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ d āĻš'āϞে n-āϤāĻŽ āĻĒāĻĻ an = a + (n - 1)d (āĻļুāĻĻ্āϧ)।
āωāϤ্āϤ⧰: (C) P, Q āφ⧰ু R āφāϟাāχāĻ•েāχāϟা āϏāϤ্āϝ


āĻĒ্ā§°āĻļ্āύ ā§¨ā§Š: -1, 3, 7, 11, ... 95 AP āϟোā§° āĻŽুāĻ  āĻĒāĻĻā§° āϏংāĻ–্āϝা āωāϞিāĻ“ā§ąাā§° āϏ্āϤ⧰āϏāĻŽূāĻš āϏāϜাāχ āϞিāĻ–া :
(i) -1 + 4n - 4 = 95
(ii) n = 25
(iii) an = 95
(iv) -1 + (n - 1)4 = 95

āϏāĻŽাāϧাāύ:
āĻĒ্ā§°āĻĨāĻŽ āϧাāĻĒ: an = 95 āĻĒ্ā§°āĻ•াāĻļ āϕ⧰া (iii)
āĻĻ্āĻŦিāϤীāϝ় āϧাāĻĒ: āϏূāϤ্ā§°āϤ āĻŽাāύ āĻŦāĻšুā§ąাāχ -1 + (n - 1)4 = 95 (iv)
āϤৃāϤীāϝ় āϧাāĻĒ: āĻŦ্ā§°েāĻ•েāϟ āĻ­াāĻ™ি -1 + 4n - 4 = 95 (i)
āϚāϤুā§°্āĻĨ āϧাāĻĒ: āϏāĻŽাāϧাāύ āϕ⧰ি n = 25 (ii)
āωāϤ্āϤ⧰: (C) (iii)→(iv)→(i)→(ii)


āĻĒ্ā§°āĻļ্āύ ⧍ā§Ē: āĻāϟা āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° āĻĒ্ā§°āĻĨāĻŽ āϤিāύিāϟা āĻĒāĻĻ āĻ•্ā§°āĻŽে b, c āφ⧰ু 2b āĻš'āϞে b āφ⧰ু c ā§° āĻ…āύুāĻĒাāϤ āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āϝিāĻšেāϤু āĻĒāĻĻ āϤিāύিāϟা (b, c, 2b) āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϤ āφāĻ›ে, ∴ āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ āϏāĻŽাāύ āĻš'āĻŦ।
c - b = 2b - c
⇒ c + c = 2b + b
⇒ 2c = 3b
⇒ b / c = 2 / 3
āωāϤ্āϤ⧰: b āφ⧰ু c ā§° āĻ…āύুāĻĒাāϤ (b : c) = 2 : 3।


āĻĒ্ā§°āĻļ্āύ ⧍ā§Ģ: āϤিāύি āĻ…ংāĻ•āĻŦিāĻļিāώ্āϟ āĻāχ āϧāύাāϤ্āĻŽāĻ• āϏংāĻ–্āϝাā§° āĻ…ংāĻ• āϤিāύāϟাāχ AP āĻ—āĻ āύ āϕ⧰ে āφ⧰ু āϏিāĻšঁāϤ⧰ āϏāĻŽāώ্āϟি 15। āĻ…ংāĻ•āĻ•েāχāϟা āĻ“āϞোāϟাāχ āĻĒোā§ąা āϏংāĻ–্āϝাāϟো āĻŽূāϞ āϏংāĻ–্āϝাāϟোāϤāĻ•ৈ 594 āĻ•āĻŽ। āϏংāĻ–্āϝাāϟো āύিā§°্āĻŖāϝ় āϕ⧰া ।
āϏāĻŽাāϧাāύ:
āϧ⧰ো āϤিāύি āĻ…ংāĻ•āϝুāĻ•্āϤ āϏংāĻ–্āϝাāϟোā§° āĻ…ংāĻ• āϤিāύিāϟা āĻ•্ā§°āĻŽে (a - d), a, āφ⧰ু (a + d)।
āĻĒ্ā§°āĻĨāĻŽ āϚ⧰্āϤāĻŽāϤে, āĻ…ংāĻ• āϤিāύিāϟাā§° āϏāĻŽāώ্āϟি = 15
⇒ (a - d) + a + (a + d) = 15
⇒ 3a = 15
⇒ a = 5

āĻ…āϤāĻāĻŦ, āĻ…ংāĻ• āϤিāύিāϟা āĻš'āϞ: (5 - d), 5, āφ⧰ু (5 + d)।
āĻŽূāϞ āϏংāĻ–্āϝাāϟো = 100(5 - d) + 10(5) + 1(5 + d)
= 500 - 100d + 50 + 5 + d
= 555 - 99d

āĻ…ংāĻ•āϏāĻŽূāĻš āĻ“āϞোāϟাāχ āϞিāĻ–িāϞে āĻĒোā§ąা āϏংāĻ–্āϝাāϟো = 100(5 + d) + 10(5) + 1(5 - d)
= 500 + 100d + 50 + 5 - d
= 555 + 99d

āĻĻ্āĻŦিāϤীāϝ় āϚ⧰্āϤāĻŽāϤে,
(āĻŽূāϞ āϏংāĻ–্āϝা) - (āĻ“āϞোāϟাāχ āĻĒোā§ąা āϏংāĻ–্āϝা) = 594
⇒ (555 - 99d) - (555 + 99d) = 594
⇒ 555 - 99d - 555 - 99d = 594
⇒ -198d = 594
⇒ d = 594 / (-198)
⇒ d = -3

āĻ…āϤāĻāĻŦ, āĻ…ংāĻ• āϤিāύিāϟা āĻš'āϞ:
āĻļāϤāϕ⧰ āĻ…ংāĻ• = 5 - (-3) = 8
āĻĻāĻšāϕ⧰ āĻ…ংāĻ• = 5
āĻāĻ•āϕ⧰ āĻ…ংāĻ• = 5 + (-3) = 2

āωāϤ্āϤ⧰: āύিā§°্āĻŖেāϝ় āϏংāĻ–্āϝাāϟো 852।

📌 SEBA Class 10 Maths Chapter 5 Arithmetic Progression (āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤি) — āĻ…āύুāĻļীāϞāύী 5.2 āϚāĻŽু āϏাā§°াংāĻļ

āĻ›েāĻŦা (SEBA) Class 10 maths chapter 5 exercise 5.2 assamese medium āϤ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° (Arithmetic Progression) n-āϤāĻŽ āĻĒāĻĻ (nth term) āύিā§°্āĻŖāϝ়ā§° āĻŦিāĻ­িāύ্āύ āĻ—াāĻŖিāϤিāĻ• āύিāϝ়āĻŽ āφ⧰ু āĻŦ্āĻ¯ā§ąāĻšাā§°িāĻ• āϏāĻŽāϏ্āϝাāϏāĻŽূāĻš āϏāĻŽাāϧাāύ āϕ⧰া āĻšৈāĻ›ে। āϝāĻĻি āφāĻĒুāύি Class 10 5.2 assamese new math solution pdf download āĻŦা āϏāĻŽ্āĻĒূā§°্āĻŖ āĻĒ্ā§°āĻļ্āύোāϤ্āϤ⧰ āĻŦিāϚাā§°ি āφāĻ›ে, āϤেāύ্āϤে āĻāχ āĻ…āύুāĻļীāϞāύীā§° āĻŽুāĻ–্āϝ āϏূāϤ্ā§° āφ⧰ু āύিāϝ়āĻŽāϏāĻŽূāĻš āĻŦুāϜি āϞোā§ąাāϟো āĻ…āϤিāĻļāϝ় āĻĒ্ā§°āϝ়োāϜāύীāϝ়।

🔑 āĻ…āύুāĻļীāϞāύী 5.2 ā§° āĻŽুāĻ–্āϝ āϧাā§°āĻŖাāϏāĻŽূāĻš (Key Concepts & Formulas):

  • n-āϤāĻŽ āĻĒāĻĻā§° āϏূāϤ্ā§° (Formula for General/nth Term): āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিā§° n-āϤāĻŽ āĻĒāĻĻ āύিā§°্āĻŖāϝ়ā§° āĻŽূāϞ āϏূāϤ্ā§°āϟো āĻš'āϞ: an = a + (n - 1)d
    āϝ'āϤ, a = āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ, d = āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰, n = āĻĒāĻĻā§° āϏংāĻ–্āϝা, āφ⧰ু an = n-āϤāĻŽ āĻĒāĻĻ।
  • āĻĒāĻĻā§° āϏংāĻ–্āϝা (Value of n): āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϤ āĻĒāĻĻā§° āϏংāĻ–্āϝা 'n' āϏāĻĻাāϝ় āĻāϟা āϧāύাāϤ্āĻŽāĻ• āĻ…āĻ–āĻŖ্āĻĄ āϏংāĻ–্āϝা (Positive Integer) āĻš'āĻŦ āϞাāĻ—ে। n ā§° āĻŽাāύ āĻ•েāϤিāϝ়াāĻ“ āĻ‹āĻŖাāϤ্āĻŽāĻ• āĻŦা āĻ­āĻ—্āύাংāĻļ āĻš'āĻŦ āύোā§ąাā§°ে।
  • āĻļেāώ⧰ āĻĢাāϞ⧰ āĻĒā§°া n-āϤāĻŽ āĻĒāĻĻ: āĻļেāώ⧰ āĻĢাāϞ⧰ āĻĒā§°া n-āϤāĻŽ āĻĒāĻĻ āύিā§°্āĻŖāϝ় āϕ⧰িāĻŦāϞৈ āϏāĻŽাāύ্āϤ⧰ āĻĒ্ā§°āĻ—āϤিāϟো āĻ“āϞোāϟাāĻ•ৈ āϞিāĻ–ি āĻĒ্ā§°āĻĨāĻŽ āĻĒāĻĻ a = āĻļেāώ āĻĒāĻĻ (l) āφ⧰ু āϏাāϧাā§°āĻŖ āĻ…āύ্āϤ⧰ -d āϞৈ āϏāĻŽাāϧাāύ āϕ⧰া āĻšāϝ়।

❓ āĻĒ্ā§°াāϝ়েāχ āϏোāϧা āĻĒ্ā§°āĻļ্āύāϏāĻŽূāĻš (Frequently Asked Questions - FAQs)

Q1. Class 10 maths 5.2 assamese medium question answer āĻŦোā§°āϤ āĻ•োāύো āĻāϟা āϏংāĻ–্āϝা AP ā§° āĻĒāĻĻ āĻšāϝ়āύে āύāĻšāϝ় āĻ•েāύেāĻ•ৈ āĻĒā§°ীāĻ•্āώা āϕ⧰া āĻšāϝ়?

Ans: āϏংāĻ–্āϝাāϟোāĻ• an āĻŦুāϞি āϧ⧰ি āϏূāϤ্ā§° an = a + (n - 1)d ā§° āĻĒā§°া n ā§° āĻŽাāύ āωāϞিāĻ“ā§ąা āĻšāϝ়। āϝāĻĻি n ā§° āĻŽাāύ āĻāϟা āϧāĻŖাāϤ্āĻŽāĻ• āĻ…āĻ–āĻŖ্āĻĄ āϏংāĻ–্āϝা āĻšāϝ়, āϤেāύ্āϤে āϏংāĻ–্āϝাāϟো AP āϟোā§° āĻĒāĻĻ āĻš'āĻŦ, āύāĻš'āϞে āύāĻšāϝ়।

Q2. Class 10 5.2 assamese new math solution pdf download āĻ•িāĻĻā§°ে āϕ⧰িāĻŦ āĻĒাā§°ি?

Ans: āφāĻĒুāύি āφāĻŽাā§° āĻāχ ā§ąেāĻŦāĻ›াāχāϟ⧰ āĻĒā§°াāχ Class 10 Chapter 5 Exercise 5.2 ā§° āϏāĻŽ্āĻĒূā§°্āĻŖ āϏāĻŽাāϧাāύ āĻŽোāĻŦাāχāϞ āĻŦা āĻ•āĻŽ্āĻĒিāωāϟাā§°āϤ āϏāĻšাāϜে āĻĒāĻĸ়িāĻŦ āφ⧰ু āĻĒ্ā§°āϝ়োāϜāύে āϏংā§°āĻ•্āώāĻŖ āϕ⧰ি ā§°াāĻ–িāĻŦ āĻĒাā§°িāĻŦ।

Q3. āĻ…āύুāĻļীāϞāύী 5.2 class 10 ā§° āĻĒā§°া SEBA āĻŽেāϟ্ā§°িāĻ• āĻĒā§°ীāĻ•্āώাāϤ āĻ•ি āϧ⧰āĻŖā§° āĻĒ্ā§°āĻļ্āύ āφāĻšে?

Ans: āϏাāϧাā§°āĻŖāϤে āύিā§°্āĻĻিāώ্āϟ āĻĒāĻĻ āύিā§°্āĻŖāϝ় āϕ⧰া (āϝেāύে: 30āϤāĻŽ āĻĒāĻĻ), āϞুāĻĒ্āϤ āĻĒāĻĻ āύিā§°্āĻŖāϝ়, āĻŦিāĻ­াāϜ্āϝ āϏংāĻ–্āϝাā§° āϏংāĻ–্āϝা āωāϞিāĻ“ā§ąা (āϝেāύে: 7 ā§°ে āĻŦিāĻ­াāϜ্āϝ 3 āĻ…ংāϕ⧰ āϏংāĻ–্āϝা) āφ⧰ু āϚ⧰্āϤāĻ­িāϤ্āϤিāĻ• 2 ā§° āĻĒā§°া 4 āύāĻŽ্āĻŦā§°ā§° āĻĒ্ā§°āĻļ্āύ āϏোāϧা āĻšāϝ়।

📚 āĻĒāĻ°ā§ąā§°্āϤী āĻ…āύুāĻļীāϞāύীāϞৈ āϝাāĻ“āĻ• (Next Exercise):

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