Find the derivative of f(x) = tan x at x = 0
Derivative of a function f(x) at any real number a is given by –
{where h is a very small positive number}
∴ derivative of cos x at x = 0 is given as –
∵ we can’t find the limit by direct substitution as it gives 0/0 (indeterminate form)
∴ Use the formula: {sandwich theorem}
∴ f’(0) = 1
Hence,
Derivative of f(x) = tan x at x = 0 is 1