What does cos(arctan(3π4)) equal?

1 Answer

cos(arctan(3π4))=416+9π2

Explanation:

We are looking for the cosine function of an angle A. The angle A whose tangent =3π4

A=arctan(3π4) it is an angle

Just imagine a right triangle with angle A with opposite side =3π
and with adjacent side =4. Then we have a hypotenuse =42+(3π)2=16+9π2

cosA=416+9π2