Question

Sabendo que A= raiz (2)/2 + cos 3x + cos x/2, determine o valor de A.

Answer 1

$A=\frac{ \sqrt{2} }{2}+cos3x + cos\frac{x}{2} \\ arcos(90)=0 \\ arcos(540)=-1\\A= \frac{ \sqrt{2} }{2}-1+ 0=\frac{ \sqrt{2} }{2}-1$