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Trigonometry Question?

Suppose csc(90-θ)=3/2. without using inverse trig functions, find the value of sin θ, sec θ, and cot θ

3 Answers

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  • ?
    Lv 7
    3 months ago

     csc(90 - θ) = 3/2. sin θ, 

     sin(θ) = sin(90 - sin^(-1)(2/3)), sin(θ) = -sin(90 + sin^(-1)(2/3))

     sec(θ) = sec(90 - sin^(-1)(2/3)), sec(θ) = -sec(90 + sin^(-1)(2/3))

     and 

     cot(θ) = cot(90 - sin^(-1)(2/3)), cot(θ) = cot(90 + sin^(-1)(2/3)

                                                                                                                  

  • alex
    Lv 7
    3 months ago

    Hint:

    csc(90-θ)=sec(θ)=

  • 3 months ago

    sec(theta) = 3/2, cos(theta) = 2/3, sin(theta) = sqrt(1 - 4/9) = sqrt(5)/3, 

    cot(theta) = cos(theta)/sin(theta) = 2/sqrt(5).

    If theta happens to be in the 4th quadrant, the sine and cotangent will be negative.

    If theta's in the first quadrant, all of the above functions are positive.

    The fact that csc(90 - theta) > 0 shows that theta cannot be in the 2nd or 3rd quadrant.

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