# FAQ: Introduction to Linear Algebra - Vector Dot Products

This community-built FAQ covers the “Vector Dot Products” exercise from the lesson “Introduction to Linear Algebra”.

Paths and Courses
This exercise can be found in the following Codecademy content:

## FAQs on the exercise Vector Dot Products

There are currently no frequently asked questions associated with this exercise – that’s where you come in! You can contribute to this section by offering your own questions, answers, or clarifications on this exercise. Ask or answer a question by clicking reply () below.

If you’ve had an “aha” moment about the concepts, formatting, syntax, or anything else with this exercise, consider sharing those insights! Teaching others and answering their questions is one of the best ways to learn and stay sharp.

## Join the Discussion. Help a fellow learner on their journey.

You can also find further discussion and get answers to your questions over in #get-help.

Agree with a comment or answer? Like () to up-vote the contribution!

Need broader help or resources? Head to #get-help and #community:tips-and-resources. If you are wanting feedback or inspiration for a project, check out #project.

Looking for motivation to keep learning? Join our wider discussions in #community

Found a bug? Report it online, or post in #community:Codecademy-Bug-Reporting

Have a question about your account or billing? Reach out to our customer support team!

None of the above? Find out where to ask other questions here!

I’m getting conflicting answers when trying to find the angle between [-17, 22] and [0, 32]. Playing with the applet, it’s clear that the angle should be approximately 40 degrees. But when I try to calculate it, I get a value that’s very near to 90. What am I doing wrong?

>>> from numpy import dot, arccos
>>> from math import degrees
>>> a = [-17, 22]
>>> b = [0, 32]
>>> dot_ab = dot(a, b)
>>> dot_ab
704
>>> mag_a = dot(a, a)
>>> mag_a
773
>>> mag_b = dot(b, b)
>>> mag_b
1024
>>> angle_ab = arccos(dot_ab / (mag_a * mag_b))
>>> degrees(angle_ab)
89.94904158653507
1 Like

The result of mag_b is wrong, it should be:
mag_b = √(0^2 + 32^2)
mag_b = 32