Question

How does Tan^-1[-2/2] = -Pi/4? How does Tan^-1[-2/2] = -Pi/4? @Mathematics

Answer 1

Tan^-1 means the inverse of tangent, not tangent to the -1 power.

Tan^-1 x = "theta" means tan "theta" = x

Tan^-1 [-2/2] is basically asking at what angle does the tangent equal [-2/2] ?

Answer 2

Yes, I knew this but converting that to theta? not sure how

Answer 3

Also, when working with the inverse tangent function, the angle will be between -Pi/2 and Pi/2 (in radians) -90 and 90 (if you are working in degrees).

Answer 4

Thanks but how would you know that it is equal to Pi/2?

Answer 5

Anyone home?

Answer 6

Sorry had to go put my daughter to bed.

Answer 7

First of all -2/2 = -1
I usually have a chart of the basic angles on a unit circle (ie all multiple of 30 and 45 that are between o and 360) in both radians and degrees

Answer 8

Here is a picture of a unit circle.

http://withfriendship.com/images/b/8803/Unit-circle-picture.gif

Answer 9

tan "theta" is equal to the y value divided by the x value.
So, tan is going to equal negative one where x = -y

Answer 10

This occurs at 7*Pi/4 which is equal to -Pi/4.

positive value means the angle was measured in the counterclockwise direction, negative value means the angle was measured in the clockwise direction.

Answer 11

Okay, library is closing. I will have to think this over. Thanks for your help.

Answer 12

hope it helped.

Answer 13

Do the (x,y) values on the outside have something to do with x^2+y^2=1 or do you just memorize (x,y) and the corresponding theta?