Verify that the the line lies wholly in the plane.

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Alshia
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1. Question

Verify that the line with vector equation r = 2i+4j+k + t(-4i-4j-5k) lies wholly in the plane with equation 3x-2y+4z=2.

2. The attempt at a solution

r = (2-4t)i + (4+4t)j + (1-5t)k

3(2-4t)-2(4+4t)+4(1-5t) = 2
6-12t-8-8t+4-20t = 2
t = 0If t = 0, doesn't that mean that the line only intersects with the plane at 2i+4j+k? So then the line does not lie wholly on the plane. So there must be something wrong with this question.
 
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Welcome to PF!

Hi Alshia! Welcome to PF! :smile:
Alshia said:
r = (2-4t)i + (4+4t)j + (1-5t)k

6-12t-8-8t+4-20t = 2
t = 0

No, that should be (4-4t)j :wink:

(and i think the question should say r = 2i+4j+k + t(4i-4j-5k))