Perpendicular Questions

Question

For x + 5y - 2z = 6, which of these is perpendicular to it?

a) (1,5,-2)

b) (x,5y,-2z)

c) (-3,1,1)

d) (1,1,0)

I thought it was c) but that is wrong but i thought the dot product had to be zero??

(1 x -3) + (5x1) + (-2x1) = -3 + 5 -2 = 0?

Could someone please tell me what i am doing wrong, thank you :)

Comments

Just kidding, think i figured it out, dot product has to = 6 which it does for d)

Answer 1

The option C is correct.

Comments

I put C in my test and got it wrong so am very confused?

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Sorry, my answer is wrong. Please check my new answer.

Answer 2

The answer is a) (1, 5,  -2). (1, 5, -2) is the normal to the plane x+5y-2z=6 and the normal of the plane is perpendicular to the plane.

Comments

Thanks for correcting me.

Answer 3

The option A is correct.

Comments

Thank you :)