# SOLUTION: given cos(2a)=-17/18 and 0<2a< pi/2 find exact values of the six trigonometric functions. Note: you cannot us decimals in your answer

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 Question 632146: given cos(2a)=-17/18 and 0<2a< pi/2 find exact values of the six trigonometric functions. Note: you cannot us decimals in your answerAnswer by solver91311(16897)   (Show Source): You can put this solution on YOUR website! First thing to note is that since , a simple division operation shows that , forcing to be a first quadrant angle, hence all six basic trigonometric functions will be positive. So Since we know that And then a little algebra music, Sammy: From which we discard the negative root because of the interval analysis earlier to get: And likewise: From which we get: Use the following identities to get the other four functions: John My calculator said it, I believe it, that settles it