Cos2x + (sinx)^2 = 0,25

Question

Cos2x + (sinx)^2 = 0,25

Comments

может sin^2x?

---

Sin2x не может быть

Answer 1

1-2(sinx)^2+(sinx)^2=0.25
1-(sinx)^2=025
(cosx)^2=0.25
cosx=0.5                     cosx=-0.5
x=+-arccos0.5+2πn      x=+-arccos(-0.5)+2πn
x=+-π/3+2πn, n∈Z       x=+-(π-π/3)+2πn, n∈Z
x=+-π/3+2πn, n∈Z       x=+-2π/3+2πn, n∈Z