• 2021-04-14 问题

    F(x,t)=f(x+2t)+f(3x-2t),Fx(0,0)=()(0,0)=

    F(x,t)=f(x+2t)+f(3x-2t),Fx(0,0)=()(0,0)=

  • 2021-04-14 问题

    F(x,t)=f(x2t)f(3x-2t),Fx(0,0)=()(0,0)=()。

    F(x,t)=f(x2t)f(3x-2t),Fx(0,0)=()(0,0)=()。

  • 2021-04-14 问题

    F(x,t)=f(x+2t)+f(3x-2t),Fx(0,0)=()(0,0)=()。

    F(x,t)=f(x+2t)+f(3x-2t),Fx(0,0)=()(0,0)=()。

  • 2022-06-05 问题

    一空间曲线由参数方程x=t y=sin(2t) , -3<t<3z=cos(3t*t)表示,绘制这段曲线可以由下列哪组语句完成。 A: t=-3:0.1:3;x=t;y=sin(2*t);z=cos(3*t.*t);plot3(x, y, z, t) B: t=-3:0.1:3;x=t;y=sin(2*t);z=cos(3*t*t);plot3(x, y, z) C: t=-3:0.1:3;y=sin(2*t);z=cos(3*t.*t);plot3(x, y, z) D: t=-3:0.1:3;x=t;y=sin(2*t);z=cos(3*t.*t);plot3(x, y, z) E: x=-3:0.1:3;y=sin(2*x);z=cos(3*x.*x);plot3(x, y, z)

    一空间曲线由参数方程x=t y=sin(2t) , -3<t<3z=cos(3t*t)表示,绘制这段曲线可以由下列哪组语句完成。 A: t=-3:0.1:3;x=t;y=sin(2*t);z=cos(3*t.*t);plot3(x, y, z, t) B: t=-3:0.1:3;x=t;y=sin(2*t);z=cos(3*t*t);plot3(x, y, z) C: t=-3:0.1:3;y=sin(2*t);z=cos(3*t.*t);plot3(x, y, z) D: t=-3:0.1:3;x=t;y=sin(2*t);z=cos(3*t.*t);plot3(x, y, z) E: x=-3:0.1:3;y=sin(2*x);z=cos(3*x.*x);plot3(x, y, z)

  • 2021-04-14 问题

    一空间曲线由参数方程x=ty=sin(2t) , -3&lt;t&lt;3z=cos(3t*t)表示,绘制这段曲线可以由下列哪组语句完成。? t=-3:0.1:3;x=t;y=sin (2*t);z=cos (3*t.*t);plot3(x, y, z)|t=-3:0.1:3;x=t;y=sin (2*t);z=cos (3*t*t);plot3(x, y, z)|t=-3:0.1:3;y=sin (2*t);z=cos (3*t.*t);plot3 (x, y, z)|t=-3:0.1:3;x=t;y=sin (2*t);z=cos (3*t.*t);plot3(x, y, z, t)

    一空间曲线由参数方程x=ty=sin(2t) , -3&lt;t&lt;3z=cos(3t*t)表示,绘制这段曲线可以由下列哪组语句完成。? t=-3:0.1:3;x=t;y=sin (2*t);z=cos (3*t.*t);plot3(x, y, z)|t=-3:0.1:3;x=t;y=sin (2*t);z=cos (3*t*t);plot3(x, y, z)|t=-3:0.1:3;y=sin (2*t);z=cos (3*t.*t);plot3 (x, y, z)|t=-3:0.1:3;x=t;y=sin (2*t);z=cos (3*t.*t);plot3(x, y, z, t)

  • 2022-06-09 问题

    设\(z = {e^{x - 2y}}\),而\(x = \sin t,\;y = {t^3},\)则\( { { dz} \over {dt}} = \)( ) A: \({e^{\sin t - 2{t^3}}}\) B: \({e^{\sin t - 2{t^3}}}\left( {\cos t - 6{t^2}} \right)\) C: \({e^{\sin t - 2{t^3}}}\ {\sin t } \) D: \({e^{\sin t - 2{t^3}}}\,{t^3}\)

    设\(z = {e^{x - 2y}}\),而\(x = \sin t,\;y = {t^3},\)则\( { { dz} \over {dt}} = \)( ) A: \({e^{\sin t - 2{t^3}}}\) B: \({e^{\sin t - 2{t^3}}}\left( {\cos t - 6{t^2}} \right)\) C: \({e^{\sin t - 2{t^3}}}\ {\sin t } \) D: \({e^{\sin t - 2{t^3}}}\,{t^3}\)

  • 2022-06-09 问题

    设\(z = f(x,y)\),\(x = \sin t\),\(y = {t^3}\),则全导数\( { { dz} \over {dt}} = \) A: \({f'_x} \sin t+ 3{t^2}{f'_y}\) B: \({f'_x} \cos t+ {t^2}{f'_y}\) C: \({f'_x} \cos t+ 3{t^2}{f'_y}\) D: \({f'_y} \cos t+ 3{t^2}{f'_x}\)

    设\(z = f(x,y)\),\(x = \sin t\),\(y = {t^3}\),则全导数\( { { dz} \over {dt}} = \) A: \({f'_x} \sin t+ 3{t^2}{f'_y}\) B: \({f'_x} \cos t+ {t^2}{f'_y}\) C: \({f'_x} \cos t+ 3{t^2}{f'_y}\) D: \({f'_y} \cos t+ 3{t^2}{f'_x}\)

  • 2022-06-04 问题

    设\(z = {e^{x - 2y}}\),而\(x = \sin t\),\(y = {t^3}\),则全导数\( { { dz} \over {dt}} = \) A: \({e^{\sin t - {t^3}}}(\cos t - 6{t^2})\) B: \({e^{\sin t - 2{t^3}}}(\sin t - 6{t^2})\) C: \({e^{\cos t - 2{t^3}}}(\cos t - 6{t^2})\) D: \({e^{\sin t - 2{t^3}}}(\cos t - 6{t^2})\)

    设\(z = {e^{x - 2y}}\),而\(x = \sin t\),\(y = {t^3}\),则全导数\( { { dz} \over {dt}} = \) A: \({e^{\sin t - {t^3}}}(\cos t - 6{t^2})\) B: \({e^{\sin t - 2{t^3}}}(\sin t - 6{t^2})\) C: \({e^{\cos t - 2{t^3}}}(\cos t - 6{t^2})\) D: \({e^{\sin t - 2{t^3}}}(\cos t - 6{t^2})\)

  • 2022-06-14 问题

    曲线$\left\{ \matrix{ {x^2} + {y^2} + {z^2} = 9 \cr y = x \cr} \right.$的参数方程为( ). A: $$\left\{ \matrix{ x = \sqrt 3 \cos t \cr y = \sqrt 3 \cos t \cr z = \sqrt 3 \sin t \cr} \right.(0 \le t \le 2\pi )$$ B: $$\left\{ \matrix{ x = {3 \over {\sqrt 2 }}\cos t\cr y = {3 \over {\sqrt 2 }}\cos t \cr z = 3\sin t \cr} \right.(0 \le t \le 2\pi )$$ C: $$\left\{ \matrix{ x = \cos t\cr y = \cos t\cr z = \sin t \cr} \right.(0 \le t \le 2\pi )$$ D: $$\left\{ \matrix{ x = {{\sqrt 3 } \over 3}\cos t\cr y = {{\sqrt 3 } \over 3}\cos t \cr z = {{\sqrt 3 } \over 3}\sin t\cr} \right.(0 \le t \le 2\pi )$$

    曲线$\left\{ \matrix{ {x^2} + {y^2} + {z^2} = 9 \cr y = x \cr} \right.$的参数方程为( ). A: $$\left\{ \matrix{ x = \sqrt 3 \cos t \cr y = \sqrt 3 \cos t \cr z = \sqrt 3 \sin t \cr} \right.(0 \le t \le 2\pi )$$ B: $$\left\{ \matrix{ x = {3 \over {\sqrt 2 }}\cos t\cr y = {3 \over {\sqrt 2 }}\cos t \cr z = 3\sin t \cr} \right.(0 \le t \le 2\pi )$$ C: $$\left\{ \matrix{ x = \cos t\cr y = \cos t\cr z = \sin t \cr} \right.(0 \le t \le 2\pi )$$ D: $$\left\{ \matrix{ x = {{\sqrt 3 } \over 3}\cos t\cr y = {{\sqrt 3 } \over 3}\cos t \cr z = {{\sqrt 3 } \over 3}\sin t\cr} \right.(0 \le t \le 2\pi )$$

  • 2022-06-12 问题

    下列程序的结果为().change(intx,inty){intt;t=x;x=y;y=t;}main(){intx=2,y=3;change(x,y);printf("x=%d,y=%d\n",x,y);} A: A)x=3,y=2 B: B)x=2,y=3 C: C)x=2,y=2 D: D)x=3,y=3

    下列程序的结果为().change(intx,inty){intt;t=x;x=y;y=t;}main(){intx=2,y=3;change(x,y);printf("x=%d,y=%d\n",x,y);} A: A)x=3,y=2 B: B)x=2,y=3 C: C)x=2,y=2 D: D)x=3,y=3

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