2sin2x+cosx+4sinx+1=0 ...

2sin2x+cosx+4sinx+1=0 cos4x+4sin²x=1+2sin²2x 2cosx/2sin3x=cosx/2

 

2sin2x+cosx+4sinx+1=0
4sin(x)+cos(x)+4sin(x)*cos(x)+1=0
(4sin(x)+1)(cos(x)+1)=0
x=2πn-π, n∈Z
x=2πn+π, n∈Z
x=2πn-arcsin(1/4), n∈Z
x=2πn+π+arcsin(1/4), n∈Z
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cos4x+4sin²x=1+2sin²2x
4sin²(x)+cos(4x)=2-cos(4x)
cos(2x)=cos(4x)
x=πn, n∈Z
x=-π/3+πn, n∈Z
x=π/3+πn, n∈Z
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