Skip to content
Question of 68

Q.Find the vector equations of the plane passing through the points P(2, 5, -3), Q(-2, -3, 5) and R(5, 3, -3).

Uttarakhand UbseUttarakhand Board Intermediate (Class 12) 2022Subjective· 4mImportance★★★★★est
0% · 0/68 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Find two vectors in the plane from the three points, take their cross product for the normal, then write the plane equation through one point.

P(2,5,−3),Q(−2,−3,5),R(5,3,−3)P(2,5,-3),\quad Q(-2,-3,5),\quad R(5,3,-3)

PQ⃗=Q−P=(−4,−8,8),PR⃗=R−P=(3,−2,0)\vec{PQ} = Q-P = (-4,-8,8), \qquad \vec{PR} = R-P = (3,-2,0)

Normal vector n⃗=PQ⃗×PR⃗\vec n = \vec{PQ}\times\vec{PR}:

n⃗=∣i^j^k^−4−883−20∣=i^[(−8)(0)−(8)(−2)]−j^[(−4)(0)−(8)(3)]+k^[(−4)(−2)−(−8)(3)]\vec n = \begin{vmatrix}\hat i & \hat j & \hat k\\-4 & -8 & 8\\3 & -2 & 0\end{vmatrix} = \hat i[(-8)(0)-(8)(-2)] - \hat j[(-4)(0)-(8)(3)] + \hat k[(-4)(-2)-(-8)(3)]

=i^(16)−j^(−24)+k^(8+24)=16i^+24j^+32k^= \hat i(16) - \hat j(-24) + \hat k(8+24) = 16\hat i+24\hat j+32\hat k

Dividing by 8: n⃗=2i^+3j^+4k^\vec n = 2\hat i+3\hat j+4\hat k.

Vector equation of the plane through PP with normal n⃗\vec n: r⃗⋅n⃗=P⃗⋅n⃗\vec r\cdot\vec n = \vec P\cdot\vec n. …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.