Tìm: a) $\int {\frac{{{{\cos }^2}x}}}}dx}$ ; b) $\int {\left( {1 + 3{{\sin }^2}\frac{x}{2}} \right)dx}$ ; c) $\int {\frac{{2{{\cos }^3}x + 3}}{{{{\cos }^2}x}}dx}$ .

Tìm:

a) $\int {\frac{{{{\cos }^2}x}}}}dx}$ ;

b) $\int {\left( {1 + 3{{\sin }^2}\frac{x}{2}} \right)dx}$ ;

c) $\int {\frac{{2{{\cos }^3}x + 3}}{{{{\cos }^2}x}}dx}$ .

Tìm: a) \int {\frac{{{{\cos }^2}x}}}}dx}\int {\frac{{{{\cos }^2}x}}}}dx} ; b) ∫(1+3sin2x2)dx\int {\left( {1 + 3{{\sin }^2}\frac{x}{2}} \right)dx} ; c) ∫2cos3x+3cos2xdx\int {\frac{{2{{\cos }^3}x + 3}}{{{{\cos }^2}x}}dx} .