SOLUTION: Find the exact value of cos x if sin x = 5/9 and x is in Quadrant 2

Algebra ->  Trigonometry-basics -> SOLUTION: Find the exact value of cos x if sin x = 5/9 and x is in Quadrant 2      Log On


   

Question 806478: Find the exact value of cos x if sin x = 5/9 and x is in Quadrant 2
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find the exact value of cos t if sin t = 5/9 and t is in Quadrant 2
-------
sin = y/r
-----
If sin = 5/9, y = 5 and r = 9
----
Solve for "x":
x = sqrt[9^2-5^2] = sqrt(56)
But x is negative in QII so x = -sqrt(56)
-----
cos(t) = x/r = -sqrt(56)/9
--------------------------------
Cheers,
Stan H.