Question

The equation of the lines through $(-1,-1)$ and making an angle ${45}^o$ with the line $x+y=0$ are

• A. $x+1=0,x-y=0$
• B. $x-y=0,y+1=0$
• C. $x+y+2=0,y+1=0$
• D. $x+1=0,y+1=0$

Answer 1

Answer: (D)

$x+1=0,y+1=0$

$\begin{array}{c}Letequationofline,y=mx+c\\ A.T.Q,\\ \tan {45}^0=\frac{m+1}{1-m}\\ 1-m=m+1\\ m=0\\ So,equationofline,\\ x+1=0\\ y+1=0\\ Hence,optionDiscorrectanswer.\end{array}$