What's the value of it?I hope you can help me.
$$\int\frac{x}{1+\cos^2{x}}dx$$
You are right.Actually what really wanted is a definite integral .In fact,it's $$\int_{-\pi}^r\frac{x(1+\sin{x})}{1+\cos^2{x}}dx$$ But I still don't know how to value it. Thank Q for your reply.