Evaluate without a calculator COS sin1 23SolutionYou are giv

Evaluate without a calculator COS [sin^-1 (2/3)]

Solution

You are given opp/hyp, you need to find adj

opp/hyp = 2/3

adj = sqrt(hyp² - opp²)

adj = sqrt(3² - 2²)

adj = sqrt(9-4)

adj = sqrt(5)

Cos(Sin inverse 2/3) = sqrt(5)/3