trigonometry write the expression as a single real number. do not use decimal appox.?

cos(2π/3)cosπ + sin(2π/3)sinπ

can you show me how and if anyone tell me all the common angles

and a good complete unit circle with the degree, radian and the coordinates

3 Answers

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  • 1 decade ago
    Favorite Answer

    sin TT=0

    -1cos 2TT/3=-1cos120=-1(0.5)=

    =1/2

    God bless you.

  • Pope
    Lv 7
    1 decade ago

    cos(2π/3) = -1/2

    cos(π) = -1

    sin(2π/3) = √(3)/2

    sin(π) = 0

    So far as the tables and diagrams you requested, they might be found in a secondary textbook appendix. A good study strategy is to become familiar with the ratios in the 45°­–45°–90° and 30°–60°–90° triangles, and learn the signs of the trigonometric functions in the four quadrants. The key is to understand rather than memorize.

  • 1 decade ago

    we can simplify the problem by finding the numerical values of the given functions.

    cos(2pi/3) = -.5

    cos(pi) = -1

    sin(2pi/3) = squareroot(3) / 2

    sin(pi) = 0

    so,

    -.5(-1) + 0 = 1.5

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