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Find the sum of the first 18 terms of the Ap 11,8,5,3... |
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Answer» GIVEN : AP : 11,8,5,3... Difference = A2 - a1 = 8 - 11 = -3 In an AP, = 18/2 [ 2(11) + (18-1)-3 ] = 9 [ 22 + (17)-3 ] = 9 [ 22 + (-51) ] = 9 [ 22 - 51 ] = 9 [ -29] = -261 Therefore, the sum of first 12 terms is -261 |
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