Calculate the Following Integral Exactly $\pi$ $\sqrt { 2 }$ , and So On

Essay

Calculate the following integral exactly.(Your answer should not be a decimal approximating the true answer, but should be exactly equal to the true answer.Your answer may contain e, $\pi$ , $\sqrt { 2 }$ , and so on.) $\int _ { 0 } ^ { 6 } \int _ { 0 } ^ { 3 } \cos 4 y \sin ( 4 x + 5 ) d x d y$