Cosign of 45 plus 30

0.9217512697

Cos(45+30)

$Cos(45+30)\\ =cos45cos30-sin45sin30\\ =\frac{1}{\sqrt2}*\frac{\sqrt3}{2}-\frac{1}{\sqrt2}*\frac{1}{2}\\ =\frac{\sqrt3}{2\sqrt2}-\frac{1}{2\sqrt2}\\ =\frac{\sqrt3-1}{2\sqrt2}\\ =\frac{\sqrt3-1}{2\sqrt2}*\frac{\sqrt2}{\sqrt2}\\ =\frac{\sqrt2(\sqrt3-1)}{2*2}\\ =\frac{\sqrt6-\sqrt2}{4}\\$