What does the square of sin mean?

What does the square of sin mean?

Sin & sup2; α = (sin α) & sup2; is a abbreviation
For example, Sin & sup2; 30 ° = (sin 30 °) & sup2; = (1 / 2) & sup2; = 1 / 4

How much is sin120?
Isn't sin120 = sin60 equal to root 3 / 2?
Why is the answer written in 1 / 2? The address is below

Sin120 = sin (180-60) = sin180 + sin (- 60) = sin180-sin60 = 1 - (3 under the root sign) / 2, you can get the third under the root sign. In fact, you can directly convert the obtuse angle into its corresponding acute angle (complementary angle) and add the sign of the quadrant where the original obtuse angle is
For example: sin150 180-150 = 30, sin30 = 0.5 and the sin value in the second quadrant of 150 is positive, sin150 = 0.5
For example, cos 120 180-120 = 60, cos 60 = 0.5 and COS 150 in the second quadrant is negative, so cos 120 = - 0.5 can be calculated in this way
Or you can directly type in Baidu: sin120, the first line has a Baidu calculator, sin (120 °) = 0.86602540378444, obviously not 0.5

Why is sin75 equal to sin105

Sin75 = sin (180-75) you need to recite the induction

Sin75 degrees equals sin105 degrees?

105 degrees without sin