The expression is , where  is a continupus function,  and  are differentiable functions.

Consider .

Part 2 of the fundamental theorem of calculus :

If  is continuous on , .

Where  is any anti derivative of  , that is a function such that .

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Where  is anti derivative of .

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Differentiate on each side with respect to .

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Apply chain rule to find the derivative of the above expression.

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