Practicing Success
\(\int_{0}^{4π}\)\(\frac{x}{1+|cosx|}\)dx |
4π 16π 32π 64π |
16π |
\(I=\int_{0}^{4π}\frac{x}{1+||cos(4π-x)||}dx\) .......(i) \(I=\int_{0}^{4π}\frac{4π-x}{1+||cos(4π-x)||}dx\) .......(ii) Adding eq. (i) and (ii), \(2I=\int_{0}^{4π}\frac{4π}{1+||cosx||}dx⇒(\int_{0}^{4π}\frac{1}{1+||cosx||}dx)2π\) $8π\int_{0}^{π}\frac{1}{1+||cosx||}dx⇒8π(\int_{0}^{\frac{π}{2}}\frac{dx}{1+cosx}+\int_{\frac{π}{2}}^{π}\frac{dx}{1-cosx})$ $8π(tan(\frac{x}{2})|_{0}^{\frac{π}{2}}+(-cot\frac{x}{2})|_{\frac{π}{2}}^{π})$ $=8π×2=16π$ |