SOLUTION: sin alpha = 3/5, pi/2 < alpha <pi, cos beta = -12/13, pi <beta< 3pi/2

Algebra ->  Trigonometry-basics -> SOLUTION: sin alpha = 3/5, pi/2 < alpha <pi, cos beta = -12/13, pi <beta< 3pi/2      Log On


   

Question 868519: sin alpha = 3/5, pi/2 < alpha
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
sin%5E2%28alpha%29%2Bcos%5E2%28alpha%29=1
%283%2F5%29%5E2%2Bcos%5E2%28alpha%29=1
cos%5E2%28alpha%29=1-9%2F25
cos%28alpha%29=0+%2B-+4%2F5
Since pi%2F2%3Calpha%3Cpi,
cos%28alpha%29=-4%2F5
..
.
.
cos%28beta%29=-12%2F13
Similarly,
sin%28beta%29=sqrt%281-144%2F169%29
sin%28beta%29=0+%2B-+5%2F13
Since pi%3Cbeta%3C%283%2F2%29pi
sin%28beta%29=-5%2F13