Finding sin(u) and cos(u) from tanu = 3/4

[stopkillingme21]

Here's the full problem: find the exact value of sin(u-v)
I'm given the following:

• tanu = 3/4, u in QIII
• sinv = 5/13, v in QII

I'm perfectly capable of doing the entire problem; my issue is that I don't know how to deduce the values of cosu and sinu from tanu = 3/4.

 

[Deleted member 4993]

Here's the full problem: find the exact value of sin(u-v)
I'm given the following:

• tanu = 3/4, u in QIII
• sinv = 5/13, v in QII

I'm perfectly capable of doing the entire problem; my issue is that I don't know how to deduce the values of cosu and sinu from tanu = 3/4.

Use

sec²(u) = 1 + tan²(u)