math
posted by sonia on .
Find the volume of the solid formed by rotating the region enclosed by
y=e^4x+3 y=0 x=0 x=0.7
this is my work
V = ∫ e^4x dx {between x=0 and x=0.7}
= 1/4 e^4x {between x=0 and x=0.7}
= 1/4 (e^2.8  e^0)
= 1/4 (e^2.8  1)
however i am etting the wrong answer pls help!!!

What you have found is the area of the region.
But you wanted the volume.
We also have to assume you are rotating about the xaxis.
in general V = piâˆ« y^2 dx
so you want
V = piâˆ«e^8x dx from 0 to .7
= (1/8)pi[e^8x] from 0 to .7
= (1.8)(pi(e^5.6  e^0)
= 105.8
You better check my arithmetic. 
Hi i checked the arithmitic and got 154.3699603 but this does not seem to be the right answer either what should I do??

Arggghhh!! I forgot the + 3 in the equation
try this
V = piâˆ«(e4x+x3)^2 dx from 0 to .7
= piâˆ«(e^8x + 6e^4x + 9)dx
= pi[(e^8x)/8 + (3/2)e^4x + 9x) from 0 to .7
= .... I will leave the arithmetic up to you, let me if it worked out this time.