证明(cosω1t+cosω2t)/2=cos(ω1-ω2)t/2×cos(ω1+ω2)t/2

证明(cosω1t+cosω2t)/2=cos(ω1-ω2)t/2×cos(ω1+ω2)t/2 t ^2 ×cosωt的原函数怎么求? sin(x+t)-sinx=2cos(x+t/2)sint/2 如何证明? matlab中怎么对下面的程序进行二维插值并画出三维视图呢?[x,y]=meshgrid(-2:1:2);t=2;Z=[(sin(t))^3 t^2 sin(t) cos(t) (sin(t))^2;t^2 sin(t) (cos(t))^4 cos(t) (sin(t))^2;t sin(t) cos(t) t^2 (sin(t))^2;sin(t) (cos(t))^3 t^2 (sin(t))^2 求解matlab绘制参数函数y=50*cos(t)-40*cos(t+7.5*((1-cos(3.1415926*t/55))-0.25*(1-cos(2*3.1415926*t/55))+36.86);x=50*sin(t)-40*sin(t+7.5*((1-cos(3.1415926*t/55))-0.25*(1-cos(2*3.1415926*t/55))+36.86);就是绘制这个方程的函数图象,t是 高中三角函数证明y=-t^2/2 + 1/2设t=tanθ及y=[(cos^2θ-sin^2θ)/2sinθcosθ ] * tanθ证明y=-t^2/2 + 1/2 ∫(cos t)^2 dt =什么? (sin t) / ( 1-cos t)= 证明cos 2x cos x=1/2(cos x+cos 3x) Matlab程序：错误在哪里建立函数文件fun5.mfunction dy=fun5(t,y)dy=[(-5*sin(t)*(5*cos(t)-y(1))+5*cos(t)*(5*sin(t)-y(2)))*(5*cos(t)-y(1))./((5*cos(t)-y(1))^2+(5*sin(t)-y(2))^2),(-5*sin(t)*(5*cos(t)-y(1))+5*cos(t)*(5*sin(t)-y(2)))*(5*sin(t)- 求不定积分∫cos^2(ωt+φ)dt 设有一个随机过程为z(t)=m(t)cos(ωt+θ),式中,m(t)为广义平稳过程,其自相关函数为Rm（τ）,随机变量θ在（0,2π）上服从均匀分布,且θ与m(t)彼此统计独立.（1）证明z(t)是广义平稳的；（2）已知Rm（ 纯电感电路公式u=Ld(sinωt)/dt =ωLd(cosωt)/dt =ωLd(sinωt+pi/2)/dt中cosωt怎么推导成sinωt了 (cos a)^2 + (cos b)^2 =1证明 matlab 中如何根据这个函数 tanx=(2(cost-cos(pi/4)*sin(t)) /(2(cost-cos(pi/4))*cos(t)+1) 画出拟合曲matlab 中如何根据这个函数 tanx=(2(cost-cos(pi/4)*sin(t)) /(2(cost-cos(pi/4))*cos(t)+1) 画出(x和t)拟合曲线 t 取值范围是 MATLAB怎么画f (t) = (1+ cosπt)[u(t) − u(t − 2)]的波形 为什么在Mathematica中：In[1]:=t = Cos[2 x]; t /.Sin_[2 x_] -> 2 Sin[x] Cos[x] Out[1]:=2 Cos[x]^2 sin (ωt) / cos (ωt) = sin (ωt) / sin(ωt + π/2) = e ^ (-j.π/2) = -j 对么?sin (ωt) / cos (ωt) = sin (ωt) / sin(ωt + π/2) = e -j.π/2 = cos(-π/2) + j.sin (-π/2) = -j ,tan (ωt) = -j 那么 tan (ωt) = -j 但是sin (ωt) = (e j.ωt - e -j.