sin^2x+2sinxcosx-3cos^2x=1 求sinx

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sin^2x+2sinxcosx-3cos^2x=1求sinxsin^2x+2sinxcosx-3cos^2x=1求sinxsin^2x+2sinxcosx-3cos^2x=1求sinxsin^2x+

sin^2x+2sinxcosx-3cos^2x=1 求sinx
sin^2x+2sinxcosx-3cos^2x=1 求sinx

sin^2x+2sinxcosx-3cos^2x=1 求sinx
sin^2x+2sinxcosx-3cos^2x=1
2sinxcosx-4cos^2x=0
sinxcosx=2cos^2x
cosx(sinx-2cosx)=0
(1)cosx=0,sinx=±1
(2)sinx=2cosx
tanx=2
tan^x+1=5
1/cos^x=5
cos^x=1/5
sin^x=4/5
sinx=±2√5/5