Given csc A = 158 and that angle A is in Quadrant I, find the exact value of cos A in simplest radical form using a rational denominator.

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!