Question

Distance between two parallel planes $2x+ y + 2z = 8$ and $4x + 2y + 4z + 5 = 0$ is

• A. $\frac{3}{2}$
• B. $\frac{5}{2}$
• C. $\frac{7}{2}$
• D. $\frac{9}{2}$

Answer 1

Answer: (C)

Given planes are
$4x + 2y + 4z +5 = 0 $ ....(1)
$4x + 2y + 4z -16 = 0 $ ....(2)
$\left[d=\frac{\left|c_{1}-c_{2}\right|}{\sqrt{16+4+116}}\right]\Rightarrow d = \left|\frac{5+16}{\sqrt{16+4+16}}\right|$
$ = \frac{21}{6} = \frac{7}{2}$