Question

Thu gọn biểu thức: 

\(X=5.\cos\left(-x\right)-2.\cos\left(5\pi+x\right)+\tan\left(\dfrac{7\pi}{2}-x\right)+7\sin\left(\dfrac{11\pi}{2}-x\right)\)

Answer 1

X=5cosx-2*cos(x+pi)+tan(3/2pi-x)+7*sin(pi/2-x)

=5cosx+7cosx+2cosx-cot(pi/2-x)

=14cosx-tanx