Let's evaluate: $\cos \left(\frac{\pi }{4}\right)$

ⓘ The cosine is the x-coordinate (horizontal axis) of the point reached on the unit circle after a rotation of $\frac{\pi }{4}$ radians from the horizontal axis pointing to the right, this is a remarkable value: $\cos \left(\frac{\pi }{4}\right)$ = $\frac{\sqrt{2}}{2}$

▶Result:   $\frac{\sqrt{2}}{2}$

The numeric value of: $\frac{\sqrt{2}}{2}$ equals:

$\frac{\approx 1.4142}{2}$

▷ $\approx 0.7071$