Question

Cos(225°-150°)вычислить. Sin(225°-150°)

Answer 1

cos(225°-150°)=cos(75°)=cos(30°+45°)=cos(30°)cos(45°)-sin(30°)sin(45°)=$\frac{\sqrt{3} }{2}*\frac{\sqrt{2} }{2}-\frac{1}{2} *\frac{\sqrt{2} }{2} =\frac{\sqrt{6} -\sqrt{2} }{4}$

sin(225°-150°)=sin(75°)=sin(30°+45°)=sin(30°)cos(45°)+cos(30°)sin(45°)=$\frac{1}{2}*\frac{\sqrt{2} }{2} + \frac{\sqrt{3} }{2}*\frac{\sqrt{2} }{2}=\frac{\sqrt{6} +\sqrt{2} }{4}$