Phương trình lượng giác

D

dien0709

$\dfrac{cosx(2sinx+3\sqrt{2})-2cos^2x-1}{1+sin2x}=1$

đk:$sin2x\neq -1\to x\neq -\dfrac{\pi}{4}+k2\pi$

$pt\to sin2x+3\sqrt{2}cosx-2cos^2x-1=1+sin2x$

$\to 2cos^2x-3\sqrt{2}cosx+2=0\to (2cosx-\sqrt{2})(cosx-\sqrt{2})=0$

So đk $\to x=\dfrac{\pi}{4}+k2\pi$
 
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