Cosx/4*sin пи/5-sin x/4 * cos пи/5=-корень 2/2

Cosx/4*Sin π / 5 - Sin x/4 * Cos π/5 = - √ 2/2

- ( - Cosx/4*Sin π/5 + Sin x/4 * Cos π/5) = - √2/2

-Sin (x/4 - π/5) = - √2/2

Sin (x/4 - π/5) = √2/2

x/4 - π/5 = (-1) ⁿπ/4 + nπ, n ∈ Z

x/4 = π/5 + (-1) ⁿπ/4 + nπ, n ∈ Z

x = 4π/5 + (-1) ⁿπ + 4nπ, n ∈ Z

Sinπ/5*cosx/4-cosπ/5*sinx/4=sin (π/5-x/4) = cos (x/4+3π/10)

cos (x/4+3π/10) = - √2/2

x/4+3π/10=-3π/4+2πn U x/4+3π/10=3π/4+2πn

x/4=-21π/20+2πn U x/4=9π/20+2πn

x=-21π/5+8πn, n∈z U x=9π/5+8πn, n∈z