Official 2008 Calculus AB FRQ Discussion

Peytoncline
Fri, 09 May 2008 20:20:08 +0000

and (one more question lol)… on the one with the lake, it gave the area of the surface of the lake represented by area bounded by sin(pix) and x^3 - 4x (thus making A = sin(pix) - (x^3 - 4x))… and it gave the depth of the water to be represented by h(x) = 3 - x

that just looked like a cross-sectional problem to me… it said find the volume, so i just set it up like a cross-sectional problem made up of rectangles perpendicular to the x-axis

so, my equation was [integral from 0 to 2 of (3 - x)(sin(pix) - (x^3 - 4x)) dx], where 3-x = h… and sin(pix) - (x^3 - 4x) = b

that was right, wasn’t it?