MathematicsEasy210×since 2002Q3482If the value of the integral ∫−11cosαx1+3xdx\int\limits_{-1}^1 \frac{\cos \alpha x}{1+3^x} d x−1∫11+3xcosαxdx is 2π\frac{2}{\pi}π2.Then, a value of α\alphaα isAπ2\frac{\pi}{2}2πBπ4\frac{\pi}{4}4πCπ3\frac{\pi}{3}3πDπ6\frac{\pi}{6}6πCheck answerSkip