其实这个问题还是三角函数展开。x1=A1*[cos5tcospi/2-sin5tsinpi/2]=-A1*sin5tx2=A2*[cospicos5t+sinpisin5t]=-A2*cos5tx1+x2=A*cos(5*t+fai)=Acos5tcosfai-Asin5t*sinfai=-A2cos5t-A1sin5tAcos5tcosfai=-A2cos5t-Asin5t*sinfai=-A1sin5t就可以算了