without-using-a-calculator-determine-the-value-of-the-following-trigonometric-ex-1

Question

Without using a calculator, determine the value of the following trigonometric expression:[sin (π/21)] ^{2} + [cos (π/21)] ^{2}

Accepted Answer

1

Answer

0

Answer

-2

Answer

1/2

Without using a calculator, determine the value of the following trigonometric expression:[sin (π/21)] 2 + [cos (π/21)] 2