已知动点的运动方程为x=t,y=2l2,则其轨迹方程为: A: x=t2-t B: y=2t C: y-2x2=2 D: y+2t2=0
已知动点的运动方程为x=t,y=2l2,则其轨迹方程为: A: x=t2-t B: y=2t C: y-2x2=2 D: y+2t2=0
下列Matlab代码,能求解微分方程 y'(t) = 2*t , y(0) = 1的是( ) A: tspan = [0 5];<br> y0 = 0;<br> [t,y] = ode45(@(t,y) 2*t, tspan, y0); B: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*t, tspan, y0); C: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*y, tspan, y0); D: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*t*y, tspan, y0);
下列Matlab代码,能求解微分方程 y'(t) = 2*t , y(0) = 1的是( ) A: tspan = [0 5];<br> y0 = 0;<br> [t,y] = ode45(@(t,y) 2*t, tspan, y0); B: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*t, tspan, y0); C: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*y, tspan, y0); D: tspan = [0 5];<br>y0 = 1;<br>[t,y] = ode45(@(t,y) 2*t*y, tspan, y0);
设x=1, y=2, 下面程序段执行后x,y的取值是( )。t=xx=yy=t A: x=2 y=1 B: x=1 y=2 C: x=1 y=1 D: x=2 y=2
设x=1, y=2, 下面程序段执行后x,y的取值是( )。t=xx=yy=t A: x=2 y=1 B: x=1 y=2 C: x=1 y=1 D: x=2 y=2
一振幅为A、周期为T、波长为λ的平面简谐波沿x轴负向传播,在x=λ/2处,t=T/4时振动相位为π,则此平面简谐波的波动方程为()。 A: y=Acos(2πt/T-2πx/λ-π/2) B: y=Acos(2πt/T-2πx/λ+π/2) C: y=Acos(2πt/T+2πx/λ+π/2) D: y=Acos(2πt/T+2πx/λ-π/2)
一振幅为A、周期为T、波长为λ的平面简谐波沿x轴负向传播,在x=λ/2处,t=T/4时振动相位为π,则此平面简谐波的波动方程为()。 A: y=Acos(2πt/T-2πx/λ-π/2) B: y=Acos(2πt/T-2πx/λ+π/2) C: y=Acos(2πt/T+2πx/λ+π/2) D: y=Acos(2πt/T+2πx/λ-π/2)
一振幅为A、周期为T、波长为λ平面简谐波沿X负向传播,在X=(1/2)λ处,t=T/4时振动相位为π,则此平面简谐波的波动方程为:() A: y=Acos(2πt/T-2πx/λ-1/2π) B: y=Acos(2πt/T+2πx/λ+1/2π) C: y=Acos(2πt/T+2πx/λ-1/2π) D: y=Acos(2πt/T-2πx/λ+1/2π)
一振幅为A、周期为T、波长为λ平面简谐波沿X负向传播,在X=(1/2)λ处,t=T/4时振动相位为π,则此平面简谐波的波动方程为:() A: y=Acos(2πt/T-2πx/λ-1/2π) B: y=Acos(2πt/T+2πx/λ+1/2π) C: y=Acos(2πt/T+2πx/λ-1/2π) D: y=Acos(2πt/T-2πx/λ+1/2π)
若y(t)=f(t)*h(t),则f(2t)*h(2t)= A: y(2t)/4 B: y(2t)/2 C: y(4t)/4 D: y(4t)/2
若y(t)=f(t)*h(t),则f(2t)*h(2t)= A: y(2t)/4 B: y(2t)/2 C: y(4t)/4 D: y(4t)/2
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: \({f'_y} \cos t+ 3{t^2}{f'_x}\)
如何用Maltab求解 y'(t) = 2*t , y(0) = 0?
如何用Maltab求解 y'(t) = 2*t , y(0) = 0?
计算曲线积分\({\oint_L {({x^2} + {y^2})} ^3}ds\),其中\(L\)为圆周\(x = a\cos t,y = a\sin t(0 \le t \le 2\pi )\)。 A: \(2\pi {a^7}\) B: \(2\pi {a^6}\) C: \(2\pi {a^5}\) D: \(2\pi {a^8}\)
计算曲线积分\({\oint_L {({x^2} + {y^2})} ^3}ds\),其中\(L\)为圆周\(x = a\cos t,y = a\sin t(0 \le t \le 2\pi )\)。 A: \(2\pi {a^7}\) B: \(2\pi {a^6}\) C: \(2\pi {a^5}\) D: \(2\pi {a^8}\)
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