Simplify by referring to the appropriate triangle or trigonometric identity.
Let θ = tan-1(x) so that tan(θ) = DI5gwNqEYSCXiF8JHGQVM88hTv/521tc.
Draw a right triangle where θ is one of the acute angles and tan θ = x. If the length of the side opposite to θ is x, find the length of the side adjacent to θ and the length of the hypotenuse.
opposite side length: x
adjacent side length: 0VV1JcqyBrI=
hypotenuse length:
Now we have the following triangle.
Using this triangle, find cos(θ).