1.
\(\Leftrightarrow\left\{{}\begin{matrix}x^2-5x< 6\\x^2-5x>-6\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x^2-5x-6< 0\\x^2-5x+6>0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}-1< x< 6\\\left[{}\begin{matrix}x>3\\x< 2\end{matrix}\right.\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}-1< x< 2\\3< x< 6\end{matrix}\right.\)
2.
\(A=-3\left(cos^4x+sin^4x+2sin^2x.cos^2x-2sin^2xcos^2x\right)+2\left(sin^2x+cos^2x\right)^3-6sin^2x.cos^2x.\left(sin^2x+cos^2x\right)\)
\(=-3\left(sin^2x+cos^2x\right)^2+6sin^2x.cos^2x+2-6sin^2x.cos^2x\)
\(=-3+2=-1\)
Đúng 2
Bình luận (0)
