Q27 of 32 Page 13

For the function f (x) = x^100/100 + x^99/99 + l + x^2/2+x+1.Prove that f’(1) = 100 f’ (0).

Given,



Now, differentiating both sides w.r.t x –


)


Using algebra of derivatives –



Use:



f’(x) = x99 + x98 + ….. + x + 1


f’(1) = 199 + 198 + … + 1 + 1 (sum of total 100 ones) = 100


f’(1) = 100


As, f’(0) = 0 + 0 + ….. + 0 + 1 = 1


we can write as


f’(1) = 100×1 = 100× f’(0)


Hence,


f’(1) = 100 f’(0) ….proved

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