not a homework problem,

I know it can be done with a trignometric substituion involving sin, but if a class hasn’t covered that yet, how would you begin to integrate the mess resolving from that?

To find the Arc Length, I did

Integral from -4 to 4 of

sqrt(1+ ((d/dx)(sqrt(16-x^2)))^2)

(16-x^2) ^1/2

1/2 (16-x^2)^-1/2 X -2x

then square that, add 1, and then integrate?

it looks even messier in this textbox, but did I err somewhere, or does using trig sub (which we havn’t learned yet) make life a lot easier?