[toán 11]Giải phương trình

N

ngocthao1995

[TEX]2sinx+2cosx+sin2x+2+cos^2x-sinxcos^2x=0[/TEX]

[TEX]\Leftrightarrow 2sinx+2cosx+2sinxcosx+2+cos^2x-sinxcos^2x=0[/TEX]

[TEX]\Leftrightarrow 2(sinx+1)+2cosx(sinx+1)+cos^2x(1-sinx)[/TEX]

[TEX]\Leftrightarrow 2(sinx+1)+2cosx(sinx+1)+(1-sinx)(1+sinx)(1-sinx)=0[/TEX]

[TEX]\Leftrightarrow (sinx+1)[2+2cosx+(1-sinx)^2]=0[/TEX]

Dễ r:)
 
H

hn3

[TEX]2sinx+2cosx+sin2x+2+cos^2x-sinx.cos^2x=0[/TEX]

[TEX]2(sinx+1)+2cosx(sinx+1)-cos^2x(sinx-1)=0[/TEX]

[TEX](1+sinx)[2(1+cosx)+(1-sinx)^2]=0[/TEX]

Xong :)
 
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