cos(x)*cos(x/2)*cos(x/4)*cos(x/8).cos(x/(2^(n-1))
cos(x)*cos(x/2)*cos(x/4)*cos(x/8).cos(x/(2^(n-1))
下列函数哪些是非周期函数( )。 A: x (t)= cos8ω0t , B: x (t)= cosω0+cos2ω0t C: x (t)= sinω0t+sinω0t D: x (t)=sin3ω0t
下列函数哪些是非周期函数( )。 A: x (t)= cos8ω0t , B: x (t)= cosω0+cos2ω0t C: x (t)= sinω0t+sinω0t D: x (t)=sin3ω0t
将函数\(f(x)=\sin^4 x\)展开成Fourier级数为 ____ . A: \(f(x) = \frac{3}{8}-\frac{1}{2}\cos 2x +\frac{1}{8}cos 4x\) B: \(f(x) = \frac{1}{4}-\frac{1}{2}\cos x +\frac{3}{8}cos 4x\) C: \(f(x) = \frac{1}{4}-\frac{1}{2}\sin 2x -\frac{3}{8}cos 4x\) D: \(f(x) = \frac{3}{8}-\frac{1}{2}\sin x -\frac{1}{8}cos 4x\)
将函数\(f(x)=\sin^4 x\)展开成Fourier级数为 ____ . A: \(f(x) = \frac{3}{8}-\frac{1}{2}\cos 2x +\frac{1}{8}cos 4x\) B: \(f(x) = \frac{1}{4}-\frac{1}{2}\cos x +\frac{3}{8}cos 4x\) C: \(f(x) = \frac{1}{4}-\frac{1}{2}\sin 2x -\frac{3}{8}cos 4x\) D: \(f(x) = \frac{3}{8}-\frac{1}{2}\sin x -\frac{1}{8}cos 4x\)
下列函数哪些是非周期函数( )。 A: x (t)=sin3ω0t B: x (t)= cos8ω0t , C: x (t)= sinω0t+sin<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/d10869ee2b304465a617ab660744efff.png">ω0t D: x (t)= cosω0+cos2ω0t
下列函数哪些是非周期函数( )。 A: x (t)=sin3ω0t B: x (t)= cos8ω0t , C: x (t)= sinω0t+sin<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202012/d10869ee2b304465a617ab660744efff.png">ω0t D: x (t)= cosω0+cos2ω0t
已知cosα=-8/17,求sinα和tanα的值
已知cosα=-8/17,求sinα和tanα的值
已知\( {y^{(6)}} = \cos x \),则\( {y^{(8)}} = - \sin x \)( ).
已知\( {y^{(6)}} = \cos x \),则\( {y^{(8)}} = - \sin x \)( ).
序列x(n)=cos(3πn/8)的周期是()。 A: 3 B: 8 C: 16 D: 不存在
序列x(n)=cos(3πn/8)的周期是()。 A: 3 B: 8 C: 16 D: 不存在
【单选题】sin ( α+β ) = A. sinαcosβ-cosαsinβ B. cosαsin β-sin αcos β C. sinαcosβ+cosαsinβ D. cos αcos β-sin α sin β
【单选题】sin ( α+β ) = A. sinαcosβ-cosαsinβ B. cosαsin β-sin αcos β C. sinαcosβ+cosαsinβ D. cos αcos β-sin α sin β
【单选题】设y=sin(cos(x)),求 结果为:(本题10.0分) A. cos(cos(x))*cos(x)+ sin(cos(x))*sin(x)^2 B. - cos(cos(x))*cos(x) - sin(cos(x))*sin(x)^2 C. - cos(cos(x))*cos(x)^2 - sin(cos(x))*sin(x)^2 D. - cos(cos(x))*cos(x) ^2- sin(cos(x))*sin(x)
【单选题】设y=sin(cos(x)),求 结果为:(本题10.0分) A. cos(cos(x))*cos(x)+ sin(cos(x))*sin(x)^2 B. - cos(cos(x))*cos(x) - sin(cos(x))*sin(x)^2 C. - cos(cos(x))*cos(x)^2 - sin(cos(x))*sin(x)^2 D. - cos(cos(x))*cos(x) ^2- sin(cos(x))*sin(x)
有一只普通圆柱压缩弹簧,弹簧钢丝直径θ2mm,弹簧中径D2=20mm,螺旋角α0=8°,总圈数10圈,求弹簧的展开长度L是多少?(sin8°=0.1392,cos8°=0.9903)
有一只普通圆柱压缩弹簧,弹簧钢丝直径θ2mm,弹簧中径D2=20mm,螺旋角α0=8°,总圈数10圈,求弹簧的展开长度L是多少?(sin8°=0.1392,cos8°=0.9903)