5.5 The Substitution Rule/55

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle \int_{0}^{\pi} \sec^2\left(\frac{t}{4}\right)dt }

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle \begin{align} u &= \frac{t}{4} \\[2ex] du &= \frac{1}{4}dt \\[2ex] 4du &=dx \end{align} }

Failed to parse (Conversion error. Server ("https://en.wikipedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\begin{aligned}\int _{0}^{\pi }\sec ^{2}\left({\frac {t}{4}}\right)dt&=4\int _{0}^{\pi }\sec ^{2}(u)du\\[2ex]&=4\cdot \tan ^{2}(u)=4\cdot \tan ^{2}\left({\frac {1}{4}}\right){\bigg |}_{0}^{\pi }\\[2ex]\end{aligned}}}