Тригонометрия cos(pi/2-2x)=cosx

Question

Тригонометрия
cos(pi/2-2x)=cosx

Answer 1

Cos(π/2-2x)=cosx
sin2x-cosx=0
2sinxcosx-cosx=0
cos(2sinx-1)=0
cosx=0⇒x=π/2+πn,n∈z
2sinx-1=0
sinx=1/2⇒x=(-1)^k*π/6+πk,k∈z

Answer 2

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