Toán Lớp 10: ( d1) : y= ( m + 1 ) x -2m -2
( d2) : y = ( 2m +1 ) x – m+2
a) Tìm m (d1) vuông góc (d2)
b ) Tìm m ( d1 ) // (d2)
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 10: ( d1) : y= ( m + 1 ) x -2m -2
( d2) : y = ( 2m +1 ) x – m+2
a) Tìm m (d1) vuông góc (d2)
b ) Tìm m ( d1 ) // (d2)
Comments ( 1 )
a)\left( {{d_1}} \right) \bot \left( {{d_2}} \right)\\
\Leftrightarrow \left( {m + 1} \right).\left( {2m + 1} \right) = – 1\\
\Leftrightarrow 2{m^2} + m + 2m + 1 = – 1\\
\Leftrightarrow 2{m^2} + 3m + 2 = 0\\
\Leftrightarrow {m^2} + \dfrac{3}{2}m + 1 = 0\\
\Leftrightarrow {m^2} + 2.m.\dfrac{3}{4} + \dfrac{9}{{16}} + \dfrac{7}{{16}} = 0\\
\Leftrightarrow {\left( {m + \dfrac{3}{4}} \right)^2} + \dfrac{7}{{16}} = 0\left( {vn} \right)\\
Vậy\,m \in \emptyset \\
b)\left( {{d_1}} \right)//\left( {{d_2}} \right)\\
\Leftrightarrow \left\{ \begin{array}{l}
m + 1 = 2m + 1\\
– 2m – 2 \ne – m + 2
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
m = 0\\
2m – m \ne – 2 – 2
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
m = 0\\
m \ne – 4
\end{array} \right.\\
\Leftrightarrow m = 0\\
Vậy\,m = 0
\end{array}$