f ( x ) = sin ( 4 x ) , [ − π , π ] {\displaystyle f(x)=\sin {(4x)}{\text{,}}\quad [-\pi ,\pi ]}
(1)
u = 4 x d u = 4 d x 1 4 d u = d x {\displaystyle {\begin{aligned}u&=4x\\[2ex]du&=4dx\\[2ex]{\frac {1}{4}}du&=dx\end{aligned}}}
New upper limit: 4 π = 4 ( π ) {\displaystyle 4\pi =4(\pi )} New lower limit: − 4 π = 4 ( − π ) {\displaystyle -4\pi =4(-\pi )}