Integration Volume Question. (1 Viewer)

[seano77]

View attachment 17199

Help please?

I can get to the stage of V= π/2 [e^2y] from In4 to 0 but can't sub it in and solve it.

Answer is 15π/2 u³

Thank you.

 

[Timothy.Siu]

yeah if u've got to there u've basically finished

u just sub in ln 4 and 0. u've done the question basically...if u sub in ln 4, e^(2ln4)=16 and e^0= 1 so then the volume = pi/2(16-1)=15pi/2 units cubed

 

[seano77]

How does e^2In4=16?

 

[veloc1ty]

e^lnx = x, so 4^2 = 16

You can just put it straight into your calculator though, to be safe.