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-   -   Calculus (https://www.askmehelpdesk.com/showthread.php?t=419020)

  • Nov 24, 2009, 01:37 PM
    stewartlindsay
    Calculus
    Show that the equation of the tangent to the curve y=x3-x2 at the point where x= -1 is y=5x+3
  • Nov 25, 2009, 04:29 AM
    galactus
    I assume you're in a claculus class. By now, you should know to use proper syntax.

    What is this?: y=x3-x2.

    That is what the ^(SHIFT 6) key is for.

    Find the derivative of y and use x=-1 to find the slope at that point. It should be 5



    After all, that is what a derivative does. Then, use y=mx+b and your given points , (-1,y(-1)), to find the tangent line equation. Just plug in x, y, and m and solve for b. That's it.
  • Dec 1, 2009, 07:51 AM
    Unknown008

    Do you know of 'Garbage In Garbage Out'? It's a computer term. If you make the wrong input, it's obvious that you will have a wrong output. So, if you want proper help, try making a minimum of efforts.
  • Dec 1, 2009, 11:56 AM
    g13544055
    the person might not know of the purpose of '^'. A lot of people don't use computers, and therefore wouldn't know the syntax.. Sir andrew wiles is one example. Pay no attention to them Stewart :)
  • Dec 1, 2009, 12:05 PM
    Unknown008

    That's why we are telling him how to do it! So that next time, he may make a better input!
  • Dec 1, 2009, 12:19 PM
    g13544055

    There are nicer ways to go about informing people.

    "I assume you're in a claculus class. By now, you should know to use proper syntax.

    What is this?: y=x3-x2."

    Is not one of them, it's patronising and rude.
  • Dec 1, 2009, 12:22 PM
    Unknown008

    Well, I guess each one of us has his/her own personality and his/her own way to tell things, so long as the intention is the same.
  • Dec 1, 2009, 12:27 PM
    g13544055

    That's perfect rationalisation. Sarcasm.

    I just hope you aren't in a position of national power.
  • Dec 1, 2009, 12:32 PM
    Unknown008

    Hmm, I'm 17 by the way... so no worries about it.
  • Dec 1, 2009, 12:37 PM
    g13544055

    I'll leave it at that then, won't continue with this. For 17 your level of maths is very good.
  • Dec 1, 2009, 12:40 PM
    Unknown008

    I'll take it as a compliment, thanks! :)

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