toan

C

congtucan12

leha_hd said:
ca nha oi jup tui bai toan nay voi, gui lai cho tui ngay nha
gpt:
sin2x+cos2x-3cosx-sinx+2=0
ra den kq cuoi nhe
Bấm để xem đầy đủ nội dung ...

(cosx+sinx)2+(cosx+sinx)(cosx−sinx)−(cosx+sinx)−(2cosx−1)=0 (cosx+sinx)^2+(cosx+sinx)(cosx-sinx)-(cosx+sinx)-(2cosx-1)=0
\Leftrightarrow(cosx+sinx)(2cosx−1)−(2cosx−1)=o (cosx+sinx)(2cosx-1) -(2cosx-1)=o
\Leftrightarrow (2cosx−1)(cosx−sinx−1)=0(2cosx-1)(cosx-sinx-1)=0
\Leftrightarrow [tex]\left[\begin{cosx=\frac{1}{2}}\\{cos(x+\frac{\pi}{4})= \frac{1}{\sqrt{2}}[/tex]
\Leftrightarrow[tex]\left[\begin{x=\frac{{+}_{-} \pi}{3}+k2\pi}\\{\left[\begin{x=k2\pi}\\{x=\frac{-\pi}{2}+k2\pi} [/tex]
 
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