Homework Help: Math

Posted by NeedHelpPlz on Friday, January 13, 2012 at 10:34pm.

I don't get how you get these answers:

cos180 degree = -1
sin45 degree = root(2)/2
cos(-135) = -root(2)/2
cot(-60) = -1/root(3) or -root(3)/3

What does cos or sin do to make the answer different?

please help

Math - Steve, Saturday, January 14, 2012 at 4:17am
Draw a triangle. In this case, it extends to the left on the x-axis, and the height is zero. Cos180° = x/h = -1/1 = -1

Draw a triangle. The legs are 1,1, hypotenuse=√2.
sin = y/h = 1/√2 = √2/2

cos -135 = - cos 45 = -√2/2

Draw a triangle
cot -60 = x/y = 1/-√3 = -1/√3
Math - NeedHelpPlz, Saturday, January 14, 2012 at 8:04am
how do you know what is the side lengths for the cot-60 angle?

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