Not homework just my own revision.(adsbygoogle = window.adsbygoogle || []).push({});

If sin a = –cos b = 3/5 and a and b are both in the second quadrant, what is cos (a – b)?

Now keep getting the answer 0, but the answer is apparently 24/25, now they use the trig subtraction formula, I just did cos ((arcsin(3/5) - arccos(-3/5)) I got 0 as the answer.

Was my method wrong, where did I go wrong with it?

**Physics Forums - The Fusion of Science and Community**

# Trig question confusion.

Know someone interested in this topic? Share a link to this question via email,
Google+,
Twitter, or
Facebook

Have something to add?

- Similar discussions for: Trig question confusion.

Loading...

**Physics Forums - The Fusion of Science and Community**