Question

How would you find the exact value of cos⁻1(0) without a calculator?

Answer 1

let y = cos-1(0) and take the cos of each side

Answer 2

But, without a calculator? How would you take the cos of each side then?

Answer 3

then since trig is 98% memorization, youll have to remember what cos(y)=0 relates to

Answer 4

y = cos-1(0), just cos each side to undo the cos^-1

cos(y) = 0

Answer 5

So would the cos undo the arccos? Then leave cos(y)=0?

Answer 6

And then y=pi/2 because cos pi/2=0?
@amistre64