Results 1 to 7 of 7
Like Tree1Thanks
  • 1 Post By gp8283

Math Help - Basic integral question & sin, tan, cos.

  1. #1
    Member
    Joined
    Oct 2011
    Posts
    170
    Thanks
    3

    Basic integral question & sin, tan, cos.

    I've just been looking at some algebra called intergrals.

    f(x) = 3x^4+x^2-9x+1 = F(x)\frac{3x^5}{5}+\frac{x^3}{3}-\frac{9x^2}{2}+x+c

    I understand this fully but in the next step when he simplifies it a little he turns the \frac{x^3}{3} into \frac{1}{3}x^3

    I don't understand why he put a 1 there in place of the x^3. Where did the 1 come from? Also one other question I have which I have is:

    f(x)= \sin x = F(x)= -\cos x+c

    I have a basic understand of sin, cos and tan but what exactly do the represent when used in equations?

    Can someone just explain what these equation actually means? Thanks
    Last edited by uperkurk; October 19th 2012 at 01:04 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor MarkFL's Avatar
    Joined
    Dec 2011
    From
    St. Augustine, FL.
    Posts
    1,988
    Thanks
    734

    Re: Basic integral question & sin, tan, cos.

    \frac{x^3}{3}=\frac{1\cdot x^3}{3\cdot1}=\frac{1}{3}\cdot\frac{x^3}{1}=\frac{  1}{3}x^3

    If you look at the graph of y=-\cos(x)+C (choose any C) and then simultaneously plot the graph of y=\sin(x) you will see that the second graph represents the instantaneous rate of change of the first.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Oct 2011
    Posts
    170
    Thanks
    3

    Re: Basic integral question & sin, tan, cos.

    But that's just it, what is -cos, cos, tan, sin etc? Are they actual constants like PI=3.14 etc? Would you be able to plot a graph y=\-cos(x)+4 just so I can see what value -cos represents.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Oct 2011
    Posts
    170
    Thanks
    3

    Re: Basic integral question & sin, tan, cos.

    I've just been looking at a cheat chart and I think something like y = -cos(60)+4 the -cos(60) would represent -\frac{1}{2} ?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor MarkFL's Avatar
    Joined
    Dec 2011
    From
    St. Augustine, FL.
    Posts
    1,988
    Thanks
    734

    Re: Basic integral question & sin, tan, cos.

    I'm sorry, you stated you have a basic understanding of the trigonometric functions, so I naturally assumed that you did.

    There are many sites online that will graph functions, and to essentially teach trigonometry is beyond the scope for me in online posts. There is a great deal of online material though that can get you started. Just do a search on trigonometry.

    I highly recommend you learn this before exploring the calculus!
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Oct 2011
    Posts
    170
    Thanks
    3

    Re: Basic integral question & sin, tan, cos.

    Oh ok no problem, I thought this was still algebra, I must have been getting a bit carried away
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Newbie
    Joined
    Oct 2012
    From
    Tucson
    Posts
    4
    Thanks
    1

    Re: Basic integral question & sin, tan, cos.

    I would recommend checking out Khan Academy there are videos that you can watch for trigonometry and also practice problems for this topic.
    Thanks from uperkurk
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. (Basic) Integral
    Posted in the Calculus Forum
    Replies: 10
    Last Post: May 30th 2011, 08:44 PM
  2. integral , basic ..
    Posted in the Math Challenge Problems Forum
    Replies: 6
    Last Post: January 9th 2010, 12:56 AM
  3. help with basic integral problem?
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 2nd 2009, 06:20 PM
  4. very basic integral
    Posted in the Calculus Forum
    Replies: 11
    Last Post: June 30th 2009, 06:10 PM
  5. basic line integral question
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 26th 2009, 09:10 AM

Search Tags


/mathhelpforum @mathhelpforum