Question

Find the planes bisecting the acute angle between the planes $x-y+2x+1=0$ and $2x+y+z+2=0$

• A. $x+z-1=0$
• B. $x+z+1=0$
• C. $x-z-1=0$
• D. None of these

Answer 1

The correct option is B $x+z+1=0$

Given planes are $x-y+2z+1=0,2x+y+z+2=0$

The plane bisecting the acute angle between the planes will be $\frac{x-y+2z+1}{\sqrt{1+1+4}}=-\frac{2x+y+z+2}{\sqrt{4+1+1}}$

$⟹x+z+1=0$