Dot product AB·AC = (2)(1) + (1)(-1) + (-2)(-1) = 3. Magnitudes |AB| = sqrt(4 + 1 + 4) = 3 and |AC| = sqrt(1 + 1 + 1) = sqrt(3).

WASpecialist MathematicsQuick questions

Unit 3

Quick questions on Vectors in three dimensions (WACE Year 12 Mathematics Specialist Unit 3)

1short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What is angle at

A

Show answer

Dot product

\overrightarrow{AB}\cdot\overrightarrow{AC} = (2)(1) + (1)(-1) + (-2)(-1) = 3

. Magnitudes

|\overrightarrow{AB}| = \sqrt{4 + 1 + 4} = 3

and

|\overrightarrow{AC}| = \sqrt{1 + 1 + 1} = \sqrt{3}

Have a question we have not covered?

This dot-point answer is short enough that we have not extracted many short questions yet. Read the full dot-point answer or ask Mo, our study assistant, in the chat for follow ups.

All Specialist MathematicsQ&A pages