Question 432637
You do not even need to evaluate {{{cos^(-1) (1/2)}}}. The expression {{{sec(cos^(-1)(1/2))}}} is equivalent to {{{1/(cos(cos^(-1)(1/2)))}}}. Since cosine and arccosine are inverse functions, the end result is the argument of the function, or 1/2. Hence, it is equal to {{{1/(1/2)}}}, or 2.