y = sin ( π x 2 ) y = x {\displaystyle {\begin{aligned}&\color {red}\mathbf {y=\sin({\frac {\pi x}{2}})} &\color {royalblue}\mathbf {y=x} \\\end{aligned}}}
sin ( x π 2 ) = x x = 0 x = 1 {\displaystyle {\begin{aligned}\sin({\frac {x\pi }{2}})&=x\\x&=0\\x&=1\\\end{aligned}}}
∫ 0 1 ( sin ( x π 2 ) − x ) d x {\displaystyle \int _{0}^{1}\left(\sin \left({\frac {x\pi }{2}}\right)-x\right)dx}
∫ 0 1 ( sin ( x π 2 ) ) d x u = x π 2 d u = π 2 d x 2 π d u = d x {\displaystyle {\begin{aligned}\int _{0}^{1}\left(\sin({\frac {x\pi }{2}})\right)dx\\&u={\frac {x\pi }{2}}\\&du={\frac {\pi }{2}}dx\\&{\frac {2}{\pi }}du=dx\\\end{aligned}}}
New upper limit: ( 0 ) π 2 = 0 {\displaystyle {\frac {(0)\pi }{2}}=0}
New lower limit: ( 1 ) π 2 = π 2 {\displaystyle {\frac {(1)\pi }{2}}={\frac {\pi }{2}}}
Failed to parse (syntax error): {\displaystyle \int_{0}^{1} \left(\sin(\frac{x\pi}{2})\right)dx &= \int_{0}^{\frac{\pi}{2}} \sin(u)du }