Find the derivation of each of the following from the first principle:

x3 – 2x2 + x + 3


Let f(x) = x3 – 2x2 + x + 3

We need to find the derivative of f(x) i.e. f’(x)


We know that,


…(i)


f(x) = x3 – 2x2 + x + 3


f(x + h) = (x + h)3 – 2(x + h)2 + (x + h) + 3


Putting values in (i), we get





Using the identities:


(a + b)3 = a3 + b3 + 3ab2 + 3a2b


(a + b)2 = a2 + b2 + 2ab






Putting h = 0, we get


f’(x) = (0)2 + 2x(0) + 3x2 – 2(0) – 4x + 1


= 3x2 – 4x + 1


Hence, f’(x) = 3x2 – 4x + 1


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