Michelle R.

asked • 10/06/20

Find the exact value of the expression whenever it is defined. (If an answer is undefined, enter UNDEFINED.)

a.) sin-1 (√2⁄2)

2 Answers By Expert Tutors

By:

Al P. answered • 10/06/20

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Precalculus tutoring

Al P.

Oh, yes, the answer from the other tutor is more complete. I was only considering quadrant 1, there is the symmetrical angle in quadrant 2 (180 degrees - 45 degrees = 135 degrees). And I only considered the principal angle (i.e. 0 <= angle < 360 degrees) which is typical for inverse trig functions. Of course, every 360 degree rotation repeats things for both of these angles, though providing just the principal angle is usually implied unless the problem explicitly asks for "all angles."
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10/06/20

Michelle R.

So then the answers would all be negative if it was (-sq root 2/2) right? Because thats what the problem was, I just forgot to put the negative sign in front of the sq root 2/2.
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10/07/20

Michelle R.

What about tan^-1( - sq root 3/3?
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10/07/20

Stephen K.

tutor
I am not sure of what you are saying. The problem is not asking for the angles whose sin is negative sqroot2/2 . the negative Sign refers to this being the inverse sin function As for Tan^-1 of ( -sqroot 3/3). Answers will be in quadrant 2 and 4 where tangent is negative. this would be at 150 degrees or 5pi/6 and 330degrees or 11pi/12
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10/07/20

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