SOLUTION: I can't figure this type of trig question; evaluate inverse trig function when the number in the parenthesis is negative. I can get the answer when it is not negative inside the p

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Question 1032308: I can't figure this type of trig question; evaluate inverse trig function when the number in the parenthesis is negative. I can get the answer when it is not negative inside the parenthesis. Help please!
Example: sin^-1 * (negative of the square root of two divided by two)
thanks.
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
You have to determine which quadrant the angle resides...I use the memory device All Students Take Calculus to mean ASTC around the quadrants...
What that tells you that in
Quadrant I -- all trig functions are positive
Q II - only Sin
Q III - only Tan
Q IV - only Cos
For example, find
sin^-1 %28-sqrt%282%29%2F2%29...
We know the sin of a 45 degree angle is sqrt(2)/2, and then 45 degrees becomes your reference angle...but sin is negative in the 3rd and 4th quadrants...
Thus the angles we need are 225 and 315 degrees...
To find all solutions, we add 360n, where n is an integer...so our answer is
225 + 360n and 315 + 360n degrees...