Derivative of a function f(x) at any real number a is given by –

{where h is a very small positive number}

∴ derivative of x² – 2 at x = 10 is given as –

⇒ f’(10) = 0 + 20 = 20

Hence,

Derivative of f(x) = x² – 2 at x = 10 is 20