Results 1 to 4 of 4

Math Help - [SOLVED] definite integral

  1. #1
    Newbie
    Joined
    May 2008
    Posts
    2

    [SOLVED] definite integral

    Hey,
    This is actually a high school maths question but we're doing calculus so...?

    okay, well this is what my maths question says:

    From other sources, find the integral function of the function you were given and hence find the definite integral of your function between x=2 and x=5.

    My function is 4^x and we are able to just do this with solvers on the internet, or finding methods on the internet, so I'm fine with that. I'm just unsure about exactly what the question wants.

    Do I find the integral function of 4^x and then find the definite integral of that or do I just find the definite integral of 4^x straight out?

    Any answer would be greatly appreciated

    Thanks so much,

    Anna
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by ajay91 View Post
    Hey,
    This is actually a high school maths question but we're doing calculus so...?

    okay, well this is what my maths question says:

    From other sources, find the integral function of the function you were given and hence find the definite integral of your function between x=2 and x=5.

    My function is 4^x and we are able to just do this with solvers on the internet, or finding methods on the internet, so I'm fine with that. I'm just unsure about exactly what the question wants.

    Do I find the integral function of 4^x and then find the definite integral of that or do I just find the definite integral of 4^x straight out?

    Any answer would be greatly appreciated

    Thanks so much,

    Anna
    you want \int_2^54^x~dx = \frac {4^x}{\ln 4} \bigg|_2^5 = \frac {4^5}{\ln 4} - \frac {4^2}{\ln 4} = \frac {1008}{\ln 4} .........this is by the fundamental theorem of calculus


    so what did we learn here?

    \int a^x~dx = \frac {a^x}{\ln a} + C for a> 1

    and the fundamental theorem of calculus. which in short says, if F(x) is the anti-derivative of f(x), then \int_a^bf(x)~dx = F(b) - F(a) (this of course assumes f is integrable and all that jazz)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member wingless's Avatar
    Joined
    Dec 2007
    From
    Istanbul
    Posts
    585
    \int^{5}_{2} 4^x~dx

    First integrate the function 4^x, then apply the integration bounds. This is the easiest way to deal with it.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    May 2008
    Posts
    2
    Yay!

    Thank you so much! We've only just started work on these sorts of things in the past few days so I'm just beginning to understand where to apply what we've learnt in class!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Definite Integral Problem
    Posted in the Calculus Forum
    Replies: 3
    Last Post: April 4th 2009, 11:27 AM
  2. Need this problem solved definite integral
    Posted in the Calculus Forum
    Replies: 3
    Last Post: February 26th 2009, 12:50 PM
  3. Replies: 27
    Last Post: September 16th 2008, 12:08 AM
  4. [SOLVED] Help needed with a definite integral
    Posted in the Calculus Forum
    Replies: 10
    Last Post: September 8th 2008, 08:00 AM
  5. Definite integral to be solved
    Posted in the Calculus Forum
    Replies: 0
    Last Post: June 8th 2008, 12:31 AM

Search Tags


/mathhelpforum @mathhelpforum