(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

1. Given cos α = -24/25 in Quadrant II and sin β = -5/13 in Quadrant III, find sin (α + β).

2. Given sin α = 4/5 in Quadrant I and cos β = -12/13 in Quadrant II, find cos (α + β).

2. Relevant equations

I don't even know where to start! The textbook doesn't list any equations.

3. The attempt at a solution

I have none, other than guessing that you multiply the denominators in each problem... other than that, I don't even know how to solve these types of problems. I'm without a teacher, so I'd really like an explanation since I'm a little... really... lost about these problems. Thanks to anyone who can show me how I'd go about solving these! I need to know it for an upcoming final.

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# Homework Help: Evaluate a Trigonometric Function

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