Find the equation of the plane passing through the points (– 1, 2, 0), (2, 2, – 1) and parallel to the line
We know that the equation of plane passing through (x1,y1,z1) is given by
a(x – x1) + b(y – y1) + c(z – z1) = 0 ……(1)
So, equation of plane passing through (– 1,2,0) is
a(x + 1) + b(y – 2) + c(z – 0) = 0 ……(2)
It also passes through (2,2, – 1)
So, equation (2) must satisfy the point (2,2, – 1)
∴ a(2 + 1) + b(2 – 2) + c(– 1) = 0
⇒ 3a – c = 0 ……(3)
We know that line is parallel to plane a2x + b2y + c2z + d2 = 0 if a1a2 + b1b2 + c1c2 = 0 ……(4)
Here, the plane is parallel to line,
So,
a×1 + b×2 + c×1 = 0
⇒ a + 2b + c = 0 ……(5)
Solving equation (3) and (5) by cross multiplication we have,
⇒
⇒
∴ a = k, b = – 2k and c = 3k
Putting the value in equation (2)
k(x + 1) – 2k(y – 2) + 3k(z – 0) = 0
kx + k – 2ky + 4k + 3kz = 0
Dividing by k we have
x – 2y + 3z + 5 = 0
The required equation is x – 2y + 3z + 5 = 0