How do integrate this definite integral

Question

anonymous · Answer

attachment

anonymous · Answer

is it not ln(12.77-012T) ???

anonymous · Answer

-ln(12.77-0.12t) under the limits 60 and 10

anonymous · Answer

no it should be the negative of that i think

lgbasallote · Answer

huh? isnt that right?

anonymous · Answer

$u=12.77-.12t, du =-dt$ might as well change the limits of integration now if you like

anonymous · Answer

yes what @pavaneinstine  wrote is right

anonymous · Answer

Would du not be 0.12??

lgbasallote · Answer

lol..you were referring to ironictoaster's answer =))

anonymous · Answer

0.12 dt

anonymous · Answer

doh 
second dumb mistake i made so far today

anonymous · Answer

Hahaha, I am so confused lol.

anonymous · Answer

$u=12.77-.12t, du =-.12dt,-\frac{25}{3}du=dt$

anonymous · Answer

now it is a numerical exercise from here on in 
you good from here or still confused?

anonymous · Answer

I got the solution from teacher just there, it's a little bit different :S

anonymous · Answer

you need a calculator for this for sure

anonymous · Answer

attachment

anonymous · Answer

check that out.

anonymous · Answer

answer is about 6.09

anonymous · Answer

that looks right
ugly, but right

anonymous · Answer

@satellite73 I don't know he got the 0.12 in the denominator.

All I did was let u= 12.77-0.12T

du = 0.12 dT

int 1/u du =ln u

anonymous · Answer

ok two mistakes
the derivative of $12.77-.12t$ is $-.12$ not $.12$
that is why there is a minus sign out front

anonymous · Answer

Thats fine.

anonymous · Answer

so you get $du=-.12dt$ but you want $dt$ so you have to write $-\frac{du}{.12}=dt$

anonymous · Answer

that is where there is a $.12$ in the denominator

anonymous · Answer

Oh dividing across. doh.

anonymous · Answer

yup