How do you calculate #cos(tan^-1 (-12 / 5))#?
If you have a graphing calculator, you can simply punch in the equation.
I am using the TI-84 Plus with it in 'degree mode'
When I put in
The equation listed above I got the answer of .3846153846
Which would be rounded to .385 or .38 degrees.
A triangle with sides
Let us use