I have done questions like these before, but the ones I did were only in quadrant I. I really wish I knew how to draw the triangles on here for you, so you see everything that I am working with.

Question:

If x is in the interval and y is in the interval and cosx = and tany = , evaluate the following.

*I will put the thing to evaluate, then the answer (according to the sheet) under it, then put my attempt after*

a) sin (x + y)

Answer:

b) cos (x - y)

Answer:

c) tan (x - y)

Answer:

Okay, now I will show my attempts (for some reason I got the answer for b, as the sheet answer for a. And the answer for b as the sheet answer for a.)

a)

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b)

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c)

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