交换积分次序$\displaystyle I=\int_1^e\mathrm{d}x\int_0^{\ln x}f(x,y)\mathrm{d}y=$
A. $\displaystyle\int_0^1\mathrm{d}y\int_e^{e^y} f(x,y)\mathrm{d}x$
B. $\displaystyle\int_0^1\mathrm{d}y\int_{e^y}^e f(x,y)\mathrm{d}x$
C. $\displaystyle\int_0^1\mathrm{d}y\int_e^{\ln y} f(x,y)\mathrm{d}x$
D. $\displaystyle\int_1^e\mathrm{d}y\int_{e^y}^0 f(x,y)\mathrm{d}x$
查看答案
设 $z=e^{x-2y}$, 而 $x=\sin t, y=t^3$, 则 $\displaystyle\frac{\mathrm{d}z}{\mathrm{d}t}=$
A. $\displaystyle\cos t+3t^2$
B. $e^{\sin t-2t^3}(\cos t+3t^2)$
C. $\displaystyle\cos t-6t^2$
D. $e^{\sin t-2t^3}(\cos t-6t^2)$
下列方程表示柱面的是
A. $\displaystyle x+y+z=1$
B. $\displaystyle x^2+y^2+z=0$
C. $\displaystyle x^2+y^2=1$
D. $\displaystyle x^2+y^2-z^2=1$
设$z=y^2+\ln(xy)$, 则$\displaystyle \frac{\partial^2{z}}{\partial{y^2}}=$.
A. $\displaystyle 2-\frac{1}{y^2}$
B. $\displaystyle 2y+\frac{1}{y}$
C. $\displaystyle 2-\frac{1}{x^2}$
D. $\displaystyle 2y+\frac{1}{x}$
将二次积分$\displaystyle I=\int_0^1\int_y^{\sqrt{y}}\frac{sinx}{x}dxdy$，交换积分次序，则$I=$
A. $\displaystyle I=\int_0^1\int_{x^2}^x\frac{sinx}{x}dydx$
B. $\displaystyle I=\int_0^1\int_x^{x^2}\frac{sinx}{x}dydx$
C. $\displaystyle I=\int_{-1}^0\int_{x^2}^x\frac{sinx}{x}dydx$
D. $\displaystyle I=\int_{-1}^0\int^{x^2}_x\frac{sinx}{x}dydx$
微信支付 
支付宝支付