Question

Which of the following is not equal to sin⁡(-230°)?

sin(130°)
-sin(-50°)
sin(50°)
sin(-50°)

Answer 1

sin⁡(-230°) =sin(50°)

Explanation:

1) sin(-a) = -sina

note : 2) sina = sinb : a=b or a+b =180°

in this exercice :

sin⁡(-230°) = - sin⁡(230°) = - sin(-50°)=- (-sin(50°)) =sin(50°) because :

sin⁡(230°) = sin(-50°) because ; 230°+(-50°) =180°

sin⁡(230°) = -sin(50°)

Answer 2

sin(-50°) is not equal to sin(-230°)

Explanation:

You will be required to use a scientific calculator for this.

Step 1 : Find out the value of sin(-230°)

sin(-230°) = 0.766

Step 2 : Find out all the other values and see if they are 0.766 or not.

sin(130°) = 0.766 (It is equal to sin(-230°))

-sin(-50°) = 0.766 (It is equal to sin(-230°))

sin(50°) = 0.766 (It is equal to sin(-230°))

sin(-50°) = -0.766 (It is not equal to sin(-230°))

!!