# Math Help - Definite integral solution

1. ## Definite integral solution

Hi all,
Can you tell me if i am correct?

Evaluate "integral sign"- [(2x^3)+(3x^2)-(4x)+5).dx between limits 5(b) and 0(a).

Integrating each term individually gives:

((x^4)/2)+(x^3)-(2x^2)+(5x).

and as b=x=5 and a=x=0

{f(b)-f(a)}

[((5^4)/2)+(5^3)-(2(5)^2)+(5(5))]-[((0^4)/2)+(0^3)-(2(0)^2)+(5(0))]

[312.5+125-50+25]-[0]

=412.5

thanks
John

Correct!

3. ## Re: Definite integral solution

Originally Posted by celtic1234
Hi all,
Can you tell me if i am correct?

Evaluate "integral sign"- [(2x^3)+(3x^2)-(4x)+5).dx between limits 5(b) and 0(a).
Is this a minus sign or a hyphen?

Originally Posted by celtic1234
Integrating each term individually gives:

((x^4)/2)+(x^3)-(2x^2)+(5x).

and as b=x=5 and a=x=0

{f(b)-f(a)}

[((5^4)/2)+(5^3)-(2(5)^2)+(5(5))]-[((0^4)/2)+(0^3)-(2(0)^2)+(5(0))]

[312.5+125-50+25]-[0]

=412.5

thanks
John
Your working is fine. If the thing in red above is a minus sign then your answer is $-412.5$ but if it is a hyphen you are correct

4. ## Re: Definite integral solution

Its a hyphen-Thanks so much for your help. I really need a book that goes from the beginning of calculus and has tons of problems from the very basic right through to the more complicated ones. The book i have gives an explanation and then gives extremely hard problems to solve-there is no solutions so it makes it difficult.
Maybe books should be a separate thread.