This is what I did:
u=sq. x
2du=1/2sq.x dx
2 int. 1 to 4 ue to the u du
then integration by parts:
y=u
dv=e to the u dy
du=u2/2
v=e to the u
=ue to the u-2 int. 1 to 4 e to the uu2/2
=ue to the u-2|u2eu-eu2u (1 to 4)
=ue to the u-16e4-6e (after I pluged in 4 and 1)
Can someone please show me what I did wrong?
Thank you
Let's change the variable to something like y instead of u (which is used in the integration by parts formula.)
Let
So
or
So
Now let's do the integration by parts.
Let
and
So
Now you take it from here. And remember, bookkeeping is important! Keep track of the details; this is where you seem to have most of your problems.
-Dan
The integral is from 1 to four. After what you gave me I put:
=ye to the y-2|1 to 4 e to the y
=ye to the y-2(e to the 4tj -e to the 1st)
=ye to the y-2e to the 4th+2e
Now, do I plug in y with sq. x?
So, my final answer would be sq.xe to sq.x-2e4+2e+c???
Thank you
If you are going to be writing a lot of these (and it seems that you are) it might be fruitful for you to look into how to write these using LaTeX. See the beginning of this thread. You can also left click on the equations and a box will come up telling you what the code is.
-Dan