Đề bài

Tính:

a) $\int\limits_0^{\frac{\pi }{2}} {\sin xdx}$;

b) $\int\limits_0^{\frac{\pi }{4}} {\cos xdx}$;

c) $\int\limits_{\frac{\pi }{4}}^{\frac{\pi }{2}} {\frac{1}{{{{\sin }^2}x}}dx}$;

d) $\int\limits_0^{\frac{\pi }{4}} {\frac{1}{{{{\cos }^2}x}}dx}$;

e) $\int\limits_0^{\frac{\pi }{2}} {\left( {\sin x - 2} \right)dx}$;

g) $\int\limits_0^{\frac{\pi }{4}} {\left( {3\cos x + 2} \right)dx}$.