Объяснение:
cos(a-π/2)=sina
sina-sin(a-π/2)=sina+sin( π2-a).
sina+sin( π/2-a)=2sin(a+π2-a)/2*cos(a-π/2+a)/2=
2sinπ/4*cos(a-π/4)=√2cos(a-π/4).
Объяснение:
cos(a-π/2)=sina
sina-sin(a-π/2)=sina+sin( π2-a).
sina+sin( π/2-a)=2sin(a+π2-a)/2*cos(a-π/2+a)/2=
2sinπ/4*cos(a-π/4)=√2cos(a-π/4).