Question

Can someone please check the answer that I got please....

Answer 1

I don't think it can be done is that correct

Answer 2

is that right

Answer 3

@phi is that answer correct

Answer 4

You should know part of the answer... the integral of b(x)

but do you know how to integrate
\[ \int_4^9 x \ dx\] ??

Answer 5

@electrokid can you please help me

Answer 6

when you get time, watch
http://www.khanacademy.org/math/calculus/integral-calculus/definite_integrals/v/evaluating-simple-definite-integral

and maybe some of the videos in the intro to calculus.

Answer 7

**Can someone please check the answer that I got please....

what answer would that be ?

Answer 8

I posted it above Cannot be done

Answer 9

yes, you can do this one, but you have to integrate x dx from 4 to 9
\[ 2\int_4^9 x \ dx = ?\]

Answer 10

10

Answer 11

see
http://www.khanacademy.org/math/calculus/integral-calculus/indefinite_integrals/v/indefinite-integrals-of-x-raised-to-a-power
for how to integrate this

Answer 12

is 37 the answer

Answer 13

is that the correct answer

Answer 14

can you show your work ?

Answer 15

yup
2(10)+17=37

Answer 16

yup 2(10)+17=37

Answer 17

the 17 is correct

but how did you get the 10 ?

you have to integrate x dx
can you do that ?

Answer 18

You have to solve
\[ 2 \int_4^9 x \ dx \]
see http://www.khanacademy.org/math/calculus/integral-calculus/indefinite_integrals/v/indefinite-integrals-of-x-raised-to-a-power
for how to do this.

Answer 19

I got 10 from 2(9)-2(4)=10

Answer 20

Yes, but that is not how to do an integral. Erase that from your memory.

use the rule
\[\int x^n dx = \frac{x^{n+1}}{n+1} \]

in your problem n is 1

Answer 21

so then is the overall answer 19

Answer 22

what is the integral? It is:
\[ \int x^1 dx = \frac{x^{1+1}}{1+1} = \frac{x^2}{2}\]

we want
\[ 2\ \int x dx = 2\cdot \frac{x^2}{2}= x^2\]
however we have lower limit of 4 and an upper limit of 9.
that means you evaluate
x^2 at x=9 and subtract x^2 at x=4

can you do that ?

Answer 23

final answer 65

Answer 24

yes
\[ 2 \int_4^9 x \ dx = 65\]
now add in the integral of b(x) = 17 for the final answer.

Answer 25

final answer 82 correct?

Answer 26

yes. But if I were you, I would learn how to integrate these simple functions.
see Khan's videos.