Originally Posted by

**deragon999** [snip]

2: find the area between x=3y and x=2+y^2

I got 1/6 Mr F says: Correct. But you should say 1/6 square units.

3: find the volume of the region bounded by y=4-x^2 and y=0 which is rotated about the x axis:

i got 6pi Mr F says: Wrong. How did you get this value? $\displaystyle {\color{red}V = \pi \int_{-2}^{2} y^2 \, dx = \pi \int_{-2}^{2} (4 - x^2)^2 \, dx = \, .....}$

4: the base of a solid v is bounded by y=x^2 and y=2-x^2. find the volume if v has square cross sections

I got 32/15 (2.1333333333) Mr F says: Are you given a height? (The area of the base is 8/3).

5: a particle has the velocity v(t)=t-1/4*t^2

a) Find: the displacement between 0 and 6 seconds:

b) Explain what this means

c) find the distance travelled between 0 and 6 seconds

d) find the average velocity between 0 and 4 seconds

i got:

a) 0 Mr F says: Correct. But you should say 0 m.

b) it has arrived back at the starting point Mr F says: Correct.

c) 36m Mr F says: Wrong. How did you get this value? Have you drawn a graph of x versus t? It starts at (0, 0), has a turning point at (4, 8/3) and a t-intercept at (6, 0) .....

d) help me with this one please Mr F says: Average velocity = Displacement/Time = (8/3)/4 = .....

[snip]