∫∫(D)cosy²dxdy=∫(0,2)cosy²dy∫(1,y+1)dx (∫(a,b)表示从a到b积分)
=∫(0,2)cosy²*[(y+1)-1]dy
=∫(0,2)y*cosy²dy
=(1/2)∫(0,2)cosy²d(y²)
=(1/2)(siny²)│(0,2)
=sin4/2.
∫∫(D)cosy²dxdy=∫(0,2)cosy²dy∫(1,y+1)dx (∫(a,b)表示从a到b积分)
=∫(0,2)cosy²*[(y+1)-1]dy
=∫(0,2)y*cosy²dy
=(1/2)∫(0,2)cosy²d(y²)
=(1/2)(siny²)│(0,2)
=sin4/2.