SOLUTION: Hi, I am not sure with my answer to one of the questions for our homework, so I was hoping someone could take a look at it here. The question is If tan A = 9/40 and A is in t

Algebra ->  Trigonometry-basics -> SOLUTION: Hi, I am not sure with my answer to one of the questions for our homework, so I was hoping someone could take a look at it here. The question is If tan A = 9/40 and A is in t      Log On


   



Question 602939: Hi, I am not sure with my answer to one of the questions for our homework, so I was hoping someone could take a look at it here.
The question is
If tan A = 9/40 and A is in the first quadrant, while cos B = -4/5 and B is in the third quadrant, what is the value of sec(A+B) ?
I was thinking since sec = 1/cos, then sec(A+B) = 1/cos(A+B) and so I arrived at the answer 1/(-133/205), by using values derived from the thought that since tan = y/x, then 9 is y and 40 is x? Or is it 40=x and 9=y? Augh I'm so confused!
I am almost 100% positive this is wrong, so if it is, please tell me how to do it properly. Thank you!

Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
You have done everything exactly right... so far.

All that is left is to simplify your answer:
1%2F%28-133%2F205%29+=+-205%2F133