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: ${e^{\sin t - 2{t^3}}}\,{t^3}$

公告：维护QQ群：833371870，欢迎加入！
公告：维护QQ群：833371870，欢迎加入！
公告：维护QQ群：833371870，欢迎加入！

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: ${e^{\sin t - 2{t^3}}}\,{t^3}$

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: ${e^{\sin t - 2{t^3}}}(\cos t - 6{t^2})$

2022-06-19 问题

求微分方程[img=269x55]17da6536a9fba07.png[/img]的通解；（） A: (C15sin(2t))/exp(3t) + (C16sin(2t))/exp(3t) B: (C15cos(2t))/exp(3t) - (C16sin(2t))/exp(3t) C: (C15cos(2t))/exp(3t) + (C16cos(2t))/exp(3t) D: (C15cos(2t))/exp(3t) + (C16sin(2t))/exp(3t)

求微分方程[img=269x55]17da6536a9fba07.png[/img]的通解；（） A: (C15*sin(2*t))/exp(3*t) + (C16*sin(2*t))/exp(3*t) B: (C15*cos(2*t))/exp(3*t) - (C16*sin(2*t))/exp(3*t) C: (C15*cos(2*t))/exp(3*t) + (C16*cos(2*t))/exp(3*t) D: (C15*cos(2*t))/exp(3*t) + (C16*sin(2*t))/exp(3*t)

2022-06-07 问题

下列信号中，（）信号的频谱是连续的。 A: $x(t) = A\sin (\omega t + {\varphi _1}) + B\sin (3\omega t + {\varphi _2})$ B: $x(t) = 5\sin 30t + 3\sin \sqrt {50} t$ C: $x(t) = {e^{ - at}}\sin {\omega _0}t$

下列信号中，（）信号的频谱是连续的。 A: $x(t) = A\sin (\omega t + {\varphi _1}) + B\sin (3\omega t + {\varphi _2})$ B: $x(t) = 5\sin 30t + 3\sin \sqrt {50} t$ C: $x(t) = {e^{ - at}}\sin {\omega _0}t$

2021-04-14 问题

一空间曲线由参数方程x=ty=sin(2t) , -3<t<3z=cos(3tt)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 (2t);z=cos (3t.t);plot3(x, y, z)|t=-3:0.1:3;x=t;y=sin (2t);z=cos (3t*t);plot3(x, y, z)|t=-3:0.1:3;y=sin (2t)；z=cos (3t.t)；plot3 (x, y, z)|t=-3:0.1:3;x=t;y=sin (2t);z=cos (3t.t);plot3(x, y, z, t)

一空间曲线由参数方程x=ty=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。? 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)

2022-06-05 问题

一空间曲线由参数方程x=t y=sin(2t) , -3<t<3z=cos(3tt)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(2t);z=cos(3t.t);plot3(x, y, z, t) B: t=-3:0.1:3;x=t;y=sin(2t);z=cos(3tt);plot3(x, y, z) C: t=-3:0.1:3;y=sin(2t)；z=cos(3t.t)；plot3(x, y, z) D: t=-3:0.1:3;x=t;y=sin(2t);z=cos(3t.t);plot3(x, y, z) E: x=-3:0.1:3;y=sin(2x);z=cos(3x.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)

2022-06-09 问题

‏已知函数[img=102x27]18030256dad01f2.png[/img]，求其三阶导数，下面命令正确的是（）‍ A: syms t; G=simplify(diff(t^2sin(t),t,3)) B: syms t; G=simplify(int(t^2sin(t),t,3)) C: syms t; G=simplify(diff(t^2sin(t),t)) D: syms t; G=simplify(int(t^2sin(t),t))

‏已知函数[img=102x27]18030256dad01f2.png[/img]，求其三阶导数，下面命令正确的是（）‍ A: syms t; G=simplify(diff(t^2*sin(t),t,3)) B: syms t; G=simplify(int(t^2*sin(t),t,3)) C: syms t; G=simplify(diff(t^2*sin(t),t)) D: syms t; G=simplify(int(t^2*sin(t),t))

2022-06-19 问题

求微分方程[img=261x61]17da6536c0cca5d.png[/img]的通解；（） A: C18cos(t) - C20sin(t) - C19tcos(t) - C21tsin(t) B: C18cos(t) + C20sin(t) - C19tcos(t) - C21tsin(t) C: C18cos(t) + C20sin(t) + C19tcos(t) + C21tsin(t) D: -C18cos(t) + C20sin(t) + C19tcos(t) + C21tsin(t)

求微分方程[img=261x61]17da6536c0cca5d.png[/img]的通解；（） A: C18*cos(t) - C20*sin(t) - C19*t*cos(t) - C21*t*sin(t) B: C18*cos(t) + C20*sin(t) - C19*t*cos(t) - C21*t*sin(t) C: C18*cos(t) + C20*sin(t) + C19*t*cos(t) + C21*t*sin(t) D: -C18*cos(t) + C20*sin(t) + C19*t*cos(t) + C21*t*sin(t)

2022-07-26 问题

一阶常微分方程[img=152x26]1802e4d6075ee4f.png[/img]的通解为 A: sin(2t)/5-cos(2t)/10+Cexp(-4t) B: sin(2t)/7+cos(2t)/5-Cexp(-3t) C: sin(2t)/7-Ccos(2t)/10+Cexp(-2t) D: sin(2t)/7-cos(2t)/7+Cexp(-5*t)

一阶常微分方程[img=152x26]1802e4d6075ee4f.png[/img]的通解为 A: sin(2*t)/5-cos(2*t)/10+C*exp(-4*t) B: sin(2*t)/7+cos(2*t)/5-C*exp(-3*t) C: sin(2*t)/7-C*cos(2*t)/10+C*exp(-2*t) D: sin(2*t)/7-cos(2*t)/7+C*exp(-5*t)

2022-06-09 问题

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: $e^{\sin t-2t^3}(\cos t-6t^2)$

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: $e^{\sin t-2t^3}(\cos t-6t^2)$

1 2 3 4 5 6 7 8 9 10