Referencia: Leon W Couch Apéndice p653
cos(x \pm y)= cos(x)cos(y) \mp sen(x)sen(y) sen(x \pm y) = sen(x)cos(y) \pm cos(x) sen(y) cos\left( x \pm \frac{\pi}{2}\right) = \mp sen(x)
sen\left( x \pm \frac{\pi}{2}\right) = \pm cos(x)
cos(2x)= cos^2 (x)- sen^2(x)
sen(2x)= 2sen(x)cos(x)
2 cos^2(x) = 1 + cos(2x)
2 sen^2(x) = 1 - cos(2x)
4 cos^3(x) = 3cos(x) + cos(3x)
4 sen^3(x) = 3sen(x) + sen(3x)
Con magnitud R y fase Θ
R cos(x + \theta) = A cos(x) - B sen(x)
donde:
R = \sqrt{A^2+B^2} \theta = tan^{-1} \left( \frac{B}{A} \right) A = R cos(\theta) B = R sen(\theta)