此题与二重积分无关吧 !
f(x,y)=(sinx)^2(siny)^2,
f'=2sinxcosx(siny)^2=0,
f'=2(sinx)^2sinycosy=0,
联立解得 x=0,π/2, π, y=0,π/2, π
共9个驻点,只有 f(π/2, π/2)=1, 其余驻点的函数值均为0,
则函数值域是[0,1]
此题与二重积分无关吧 !
f(x,y)=(sinx)^2(siny)^2,
f'=2sinxcosx(siny)^2=0,
f'=2(sinx)^2sinycosy=0,
联立解得 x=0,π/2, π, y=0,π/2, π
共9个驻点,只有 f(π/2, π/2)=1, 其余驻点的函数值均为0,
则函数值域是[0,1]