Water is falling on a surface, wetting a circular area that is expanding at a rate of 10mm^2/sec. how fast is the radius of the wetted area expanding when the radius is 116mm?

Ibelieve the answer is d. 

Answer(a) cheap enough for small shops to purchase;

The bystander effect  for some reason my history teacher was talking about this 

The answer is    (d) 7/2======we have    we also  have an integral      notice how function f splits up at x = 0. there's a left piece and a right pieceso we'll need to do the same thing with our integral: split it at x = 0we use a property of integrals that allows us to split up and sum:     notice that for the piecewise function f, the function has the equationf(x) = x when x  ≤ 0. so for the integral  , f(x) = x so it changes into      for the piecewise function f, the function has the equationf(x) = x+1  when x  > 0. for the integral  , we have    therefore, back to our splitted integral: