If two planes \(\underline{r}(2,-b, 1)=4\) and \(\underline{r}(4,-1,-c)=6\) are parallel then \(\mathrm{b}, \mathrm{c}=\) \((\) A \()-(1 / 2),-2\) (B) \((1 / 2), 2\) (C) \(-(1 / 2), 2\) (D) \((1 / 2),-2\)

Short Answer

Expert verified
(D) (1/2, -1)

Step by step solution

01

Write the planes in general form

We start by writing the given planes in their general form which is \(Ax + By + Cz = D\): Plane 1: \(2x - by + z = 4\) Plane 2: \(4x - y - cz = 6\)
02

Find the normal vectors for each plane

The normal vector of a plane can be found using the coefficients of x, y, and z in the general form of the equation. For the given planes, the normal vectors are: Normal vector of Plane 1: \(\underline{n_1} = \langle 2, -b, 1 \rangle\) Normal vector of Plane 2: \(\underline{n_2} = \langle 4, -1, -c \rangle\)
03

Check if the normal vectors are proportional

Two normal vectors are proportional (parallel) if there is a constant scalar k such that \(\underline{n_1} = k \cdot \underline{n_2}\). That is, for \(\underline{n_1}\) and \(\underline{n_2}\) to be proportional: \(\frac{2}{4}=\frac{-b}{-1}=\frac{1}{-c}\) Now, we will solve these equations to find values of b and c.
04

Determine the values of b and c

From the proportionality between \(\underline{n_1}\) and \(\underline{n_2}\), we can write the following equations: \(k=\frac{2}{4} \Rightarrow k=\frac{1}{2}\) \(k=\frac{-b}{-1} \Rightarrow -b = -\frac{1}{2} \) \(k=\frac{1}{-c} \Rightarrow -c=1\) Now, solve for b using the second equation: \(-b = -\frac{1}{2} \Rightarrow b = \frac{1}{2}\) And for c using the third equation: \(-c = 1 \Rightarrow c =-1\) Therefore, we have: b = 1/2, c = -1 Matching this with the given options, we get the correct answer is: (D) (1/2, -1)

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

See all solutions

Recommended explanations on English Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free