Original
To summarize, if we suspect that a given function is the derivative of
another via the chain rule, we introduce a new variable {{MATH_95}}, where {{MATH_96}} is a likely candidate for
the inner function. We rewrite the integral
entirely in terms of {{MATH_97}}, with no {{MATH_98}} remaining in the
expression. If we can integrate this new function of {{MATH_99}}, then the
antiderivative of the original function is obtained by replacing {{MATH_100}}
by {{MATH_101}}.