Question

express the relationship between a small change in x and the corresponding change in y in the form dy=f'(x)dx

f(x)=2-acosx

Answer 1

is acos short for arccos? looks like a programing shorthand

Answer 2

if so then let

y = acos(x)

cos(y) = x

-sin(y) y' = 1

y' = -csc(y) , and we know y = acos(x)

y' = -csc(acos(x))