1. ## definite integral

I have two problems the first, x^9dx from 2b to b and I got x^10/10 so I put it in the calculator and it gave me an answer of 11215267.66 but the back of the book has a different answer. The other one is dx/sqrt(1-x^2) from 0.7 to 0 and I got -d*sqrt(1-x^2) and I also put this in the calculator and it gave me -.49989999. I did about fifteen other problems and they all came out can you tell me where I went wrong.
Thank You,
Keith

2. Originally Posted by keith
I have two problems the first, x^9dx from 2b to b and I got x^10/10 so I put it in the calculator and it gave me an answer of 11215267.66 but the back of the book has a different answer. The other one is dx/sqrt(1-x^2) from 0.7 to 0 and I got -d*sqrt(1-x^2) and I also put this in the calculator and it gave me -.49989999. I did about fifteen other problems and they all came out can you tell me where I went wrong.
Thank You,
Keith
how did you manage to get a numerical answer? what is b?

the formula for your first integral is correct, the second is not

3. Originally Posted by keith
The other one is dx/sqrt(1-x^2) from 0.7 to 0 and I got -d*sqrt(1-x^2) and I also put this in the calculator and it gave me -.49989999.
Actually

$\int\frac1{\sqrt{1-x^2}}\,dx=\arcsin x+k$

For the first one... $b<0$ or $b>0$?