SOLUTION: If {{{ sin^2(pi/9) + sin^2(2pi/9) + sin^2(3pi/9) + sin^2(4pi/9) = 9/4 }}}, without the use of a calculator, evaluate {{{ cos^2(pi/9) + cos^2(2pi/9) + cos^2(3pi/9) + cos^2(4pi/9)

SOLUTION: If {{{ sin^2(pi/9) + sin^2(2pi/9) + sin^2(3pi/9) + sin^2(4pi/9) = 9/4 }}}, without the use of a calculator, evaluate {{{ cos^2(pi/9) + cos^2(2pi/9) + cos^2(3pi/9) + cos^2(4pi/9)

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Question 1191167: If , without the use of a calculator, evaluate
Answer by greenestamps(13203) (Show Source): You can put this solution on YOUR website!

ANSWER: 7/4

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