積分的值等于:()
A.(5/3)π B.(5/6)π C.(10/7)π D.(10/11)π
設D是由不等式|x|+|y|≤1所確定的有界區(qū)域,則二重積分|x|dxdy的值是:()
A.0 B.1 C.2/3 D.1/3
設D是矩形區(qū)域:0≤x≤π/4,-1≤y≤1,則xcos2xydxdy等于:()
A.0 B.-1/2 C.1/2 D.1/4