[tex] \int\limits^\frac{\pi}{2}_\frac{\pi}{4} {(3-cos\alpha}x) \, dx [/tex] Помогите

(3x-sinx) | (п/4;п/2) = 3п/2-sin п/2 - 3п/4+sin п/4 =

=(3п/2-3п/4)-(1-√2/2) = 3п/4 - 1+√2/2