4 sin (1/4 phi + x) cos (1/4 phi - x) =

diuraikan
4*(sin(x)/sqrt(2)+cos(x)/sqrt(2))^2
disederhanakan
2*sin(x)^2+4*cos(x)*sin(x)+2*cos(x)^2
difaktorkan
2*(sin(x)+cos(x))^2