SOLUTION: let a be the root of the equation 25cos^2a + 5 cos a - 12=0 where, pie/2<a<pie then what is tan a equal to?

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Question 976405: let a be the root of the equation
25cos^2a + 5 cos a - 12=0 where, pie/2
Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
25cosa^2 + 5cosa - 12 = 0
(5cosa - 3)(5cosa + 4) = 0
cos a = 3/5 = 0.6
53.1 degs, 306.9 degs
or
cos a = -4/5 = -0.8
143.1 degs , 216.9 degs
Hope this helps:-)