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if the 3rd and the 9th terms of an AP are 4 and -8 respectively , which term of the AP is zero.please give step by step |
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Answer» Answer: 5TH term Step-by-step explanation: Given a3 = 4 a9 = -8 WKT, a = (n-1)d So, we can WRITE, a3 = a + 2d a +2d = 4.............(1) a9 = a+ 8d a + 8d = -8............(2) SUBTRACTING (1) from (2) , we get d = -2 Substituting d = -2 in (1) , we get a = 8 WKT, an = a + (n-1) d 0 = 8 + (n-1) -2 -8=(n-1)-2 4=n-1 n=5 Therefore, 0 is the 5th term of the given AP. |
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