Question

how is Cos^-1(0) solved without a calculator?

Answer 1

well how do you get 90 in the first place?

Answer 2

Thanks!

Answer 3

cos(A) gives you the x-component of the point located A degrees around the unit circle

Answer 4

so look at a unit circle on an x-y graph

Answer 5

thats much more understandable, thanks

Answer 6

you start at the point (1,0) on the unit circle and follow it around until you get to a point with x=0, i.e. somewhere along the y-axis

Answer 7

you're trying to find which angle A gives you cos(A) = 0, alternatively: cos^-1(0) = A