rút gọn hệ thức : a) P = cos(\(\frac{\pi}{2}\) + x) + cos(2\(\pi\) - x) + cos(3\(\pi\) + x) ; b) Q = 2sin(\(\frac{\pi}{2}\) + x) + sin(4\(\pi\) - x) + sin(\(\frac{3\pi}{2}\) + x) + cos(\(\frac{\pi}{2}\) + x)
Loga
Toán lớp 10
