a) tan(2x+1)tan(3x-1)=1
b) tanx + tan(x+π/4)=1
Thank You
$a)pt=>tan(2x+1)=cot(3x-1)=tan(\dfrac{\pi}{2}-3x+1)=>...$
$b)pt=>sin(2x+\dfrac{\pi}{4})=cosxcos(x+\dfrac{\pi}{4})=\dfrac{1}{2}(cos(2x+\dfrac{\pi}{4})+cos\dfrac{\pi}{4})$
có dạng $asinx+bcosx=c$