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


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