对于信号f(t)=sin2π*103+sin4π*103的最小采样频率是() A: 8kHz B: 4kHz C: 2kHz D: 1kHz
对于信号f(t)=sin2π*103+sin4π*103的最小采样频率是() A: 8kHz B: 4kHz C: 2kHz D: 1kHz
sinα-cosα=m求sin^4α+cos^4α的值
sinα-cosα=m求sin^4α+cos^4α的值
G65 H31 P#101 Q#102 R103;表示#101=#102·__1__ ·(#103)。 (A)COS (B)SIN (C)OR (D)AND
G65 H31 P#101 Q#102 R103;表示#101=#102·__1__ ·(#103)。 (A)COS (B)SIN (C)OR (D)AND
函数\(y = \cos (4 - 3x)\)的导数为( ). A: \( - 3\sin \left( {4 - 3x} \right)\) B: \(3\sin \left( {4 - 3x} \right)\) C: \(3\sin \left( {4 + 3x} \right)\) D: \( - 3\sin \left( {4 + 3x} \right)\)
函数\(y = \cos (4 - 3x)\)的导数为( ). A: \( - 3\sin \left( {4 - 3x} \right)\) B: \(3\sin \left( {4 - 3x} \right)\) C: \(3\sin \left( {4 + 3x} \right)\) D: \( - 3\sin \left( {4 + 3x} \right)\)
$\int \sin^3 x \cos x dx = $ A: $\frac{\sin^4 x}{4} +C$ B: ${\sin^4 x} +C$ C: $\frac{\cos^4 x}{4} +C$ D: $\frac{\cos^4 x}{4} +C$
$\int \sin^3 x \cos x dx = $ A: $\frac{\sin^4 x}{4} +C$ B: ${\sin^4 x} +C$ C: $\frac{\cos^4 x}{4} +C$ D: $\frac{\cos^4 x}{4} +C$
(1-sin^6α-cos^6α)/(sin^2α-sin^4α)的值
(1-sin^6α-cos^6α)/(sin^2α-sin^4α)的值
下列各组选项的两个语句运行结果不同的是? Dt[Sin[x],{x,4}] ,D[Sin[x],{x,4}]|D[Sin[x]Sin[y],x], Dt[Sin[x]Sin[y],x,Constants→y]|Dt[Sin[x]Sin[y],x] ,D[Sin[x]Sin[y],x,NonConstants→y]|Dt[x^2y^3,x,y],D[x^2y^3,x,y]
下列各组选项的两个语句运行结果不同的是? Dt[Sin[x],{x,4}] ,D[Sin[x],{x,4}]|D[Sin[x]Sin[y],x], Dt[Sin[x]Sin[y],x,Constants→y]|Dt[Sin[x]Sin[y],x] ,D[Sin[x]Sin[y],x,NonConstants→y]|Dt[x^2y^3,x,y],D[x^2y^3,x,y]
求微分方程[img=143x21]17da5f14490e50e.png[/img]的通解,实验命令为(). A: dsolve(D2y-2*Dy+5*y=sin(2*x),x)ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x) B: dsolve('D2y-2*Dy+5*y=sin(2*x)','x')ans =cos(2*x)*(sin(4*x)/17 - cos(4*x)/68 + 1/4) - sin(2*x)*(cos(4*x)/17 + sin(4*x)/68) + C1*cos(2*x)*exp(x) - C2*sin(2*x)*exp(x) C: dsolve(D2y-2*Dy+5*y=sin(2*x),'x','y')ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x)
求微分方程[img=143x21]17da5f14490e50e.png[/img]的通解,实验命令为(). A: dsolve(D2y-2*Dy+5*y=sin(2*x),x)ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x) B: dsolve('D2y-2*Dy+5*y=sin(2*x)','x')ans =cos(2*x)*(sin(4*x)/17 - cos(4*x)/68 + 1/4) - sin(2*x)*(cos(4*x)/17 + sin(4*x)/68) + C1*cos(2*x)*exp(x) - C2*sin(2*x)*exp(x) C: dsolve(D2y-2*Dy+5*y=sin(2*x),'x','y')ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x)
求微分方程[img=364x55]17da65386dfd612.png[/img]的通解; ( ) A: - cos(2*x)*exp(x)*(x/4 - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x) B: (3*sin(2*x)*exp(x))/32 - (sin(6*x)*exp(x))/32 - cos(2*x)*exp(x)*(x/4 - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x) C: - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x) D: (sin(6*x)*exp(x))/32 - cos(2*x)*exp(x)*(x/4 - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x)
求微分方程[img=364x55]17da65386dfd612.png[/img]的通解; ( ) A: - cos(2*x)*exp(x)*(x/4 - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x) B: (3*sin(2*x)*exp(x))/32 - (sin(6*x)*exp(x))/32 - cos(2*x)*exp(x)*(x/4 - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x) C: - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x) D: (sin(6*x)*exp(x))/32 - cos(2*x)*exp(x)*(x/4 - sin(4*x)/16) + C23*cos(2*x)*exp(x) + C24*sin(2*x)*exp(x)
下列计算正确的是() A: log2cos7π4=-12 B: 若f(cos x)=cos 2x,则f(sin 30°)=12 C: 若sin(π+α)=-12,则sin(4π-α)=-12 D: 设tan(π+α)=2,则sin(α-π)+cos(π-α)sin(π+α)-cos(π-α)=1
下列计算正确的是() A: log2cos7π4=-12 B: 若f(cos x)=cos 2x,则f(sin 30°)=12 C: 若sin(π+α)=-12,则sin(4π-α)=-12 D: 设tan(π+α)=2,则sin(α-π)+cos(π-α)sin(π+α)-cos(π-α)=1