Read the two statements and choose the correct option.
I. The lines with direction ratios $1, 2, -2$ and $2, -2, 1$ are perpendicular.
II. The angle between $\vec{r} = \vec{a}_1 + \lambda\vec{b}_1$ and $\vec{r} = \vec{a}_2 + \mu\vec{b}_2$ depends on $\vec{a}_1$ and $\vec{a}_2$ .

Only ICorrect answerYour answerOnly IICorrect answerYour answerBoth I and IICorrect answerYour answerNeither I nor IICorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer D

Correct answer: D

I: $1(2) + 2(-2) + (-2)(1) = -4 \ne 0$ . False.
II: the angle uses only $\vec{b}_1$ and $\vec{b}_2$ ; the points play no part. False.

Ten questions from Three-Dimensional Geometry, at your own pace.

Ten questions from Three-Dimensional Geometry, at your own pace.

Explanation