# Which of the following is an arithmetic sequence?

7. Which of the following is an arithmetic sequence? -7, 4, 15,26,… c. 21, 15.9, 2. b. -8, 6, 4,0,… d. 4, -1. 7. 13 a. 8 C. 3 Which of the following is the common difference of an arithmetic sequence whose a = 1, as = 72 1 b. 2 d. 4 9. Which of the following is the common difference of the arithmetic sequence 3a -1, 3a, 3a + 1, …? b. a C. -1 d. 1 10. Which of the following is the first positive term of the arithmetic sequence 8.-6.-4. …? 0 b. 2 d. 6 11. Which of the following is the value of a to make 3a -1, la, ba -1…an arithmetic sequence? b.-1 C. O d. 1 a.

7/ a. -7,4,15, 26, SO Since 4-67) = common difference a -15-4 = 26-15 = 11, I is the of 아 the sequence. Hence this is arithmetic progression b. -8,-6, -4,0 Since -6-68) 2 and o-E4)=4 so -6-(-8) 70-(-4), so does NOT exist. Hence this is NOT an arithmetic progression. C, 21,15,9, 220 15-21 #2 -9,50 difference Since does NOT exist. Hence this is NOT an arithmetic progression. difference common common d. 4,-1,-7, -13,- Since -1-4 7-7-61), so common difference does NOT exist. Hence this is NOT an arithmetic progression. answer is: option (a): -7,4, 15,26, …. Hence the correct
87 A₂=1, commor non difft As 7 Suppose the difference be d and the first term be Then a = atd and as = aut.d a, ( These give, at d = 1 d = 7 at get, we a, = -1 and d=2 Solving Hence the Option (b) 2 com non 2. difference is wrrect . is sequence is common 91 The arith metic 30-1, 32, 3a+19 —.. The difference is = 3a-(34-1) 1 Hence option (d) 1 is correct. 101 The arithmetic sequence is -8, -6, -4,–.. The difference is = -6-68) = 2 So rewritting the sequence . we get common -8, -8+2×1, -8+ 2*2, -8+2*3, -8+2×4 , -8 + 2×5,…. Note o is that is, -8,-6,-4, -2,0,2,4,…. not Hence the first positive term is 2. called positive. option (b) is correct. o is non-negativ

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