Question

how do i tackle this problem? which of following equals inverse cos(cos 7pi/6) ?

Answer 1

The cosine of 7pi/6 = -sqrt3/2 so now the problem is arccos(-sqrt3/2) which, of course means "give the angle whose cosine is the negative square root of 3 divided by 2" . That would be 7pi/6. The point being when you apply a funtion and its inverse to the some quantity, you end up right back where you started from. Sort of like saying "What is 6 + 3 - 3?" or what is the square root of 5 squared.