Q45 of 80 Page 239

Differentiate each of the functions with respect to ‘x’

Differentiate using first principle


Let f(x) = x2/3 ------ (i)


f(x + ∆x) =(x + ∆x)2/3 ------ (ii)


Subtracting eq. (i) from eq. (ii),


f(x + ∆x) - f(x) = (x + ∆x)2/3 - x2/3


Dividing both sides by ∆x and taking the limit,





By differentiation,




Expanding by binomial theorem, and rejecting the higher powers of ∆x as ∆x 0





Hence, the answer is .


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