Question #b9d1a

1 Answer
Nov 3, 2017

The arc length is #pi#.

Explanation:

Squaring both sides of this equation gives #y^2=1-x^2# and a little rearrangement shows this to be a circle with centre #(0, 0)# and radius 1.
The radical sign #sqrt# defines only the positive value of the bracket, so we're looking at just the half circle where y is positive.
Using half of #2pi r#, we get a result of #pi#.