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problem with the chain rule

  • 22-04-2008 05:38PM
    #1
    Closed Accounts Posts: 96 ✭✭


    hey guys im im just wondering could anyone help me with these
    two problems using the chain rule,

    question one is

    sin(3e^x-2cosx+10e^x+2sinhx)

    and question 2 is

    cos(3lnx-2sinhx+2e^x-4tanx)

    thanks in advance for anyhelp

    another question if i have 2lnx is that the same as 2/x?


Comments

  • Registered Users, Registered Users 2 Posts: 4,502 ✭✭✭chris85


    subzero12 wrote: »
    hey guys im im just wondering could anyone help me with these
    two problems using the chain rule,

    question one is

    sin(3e^x-2cosx+10e^x+2sinhx)

    and question 2 is

    cos(3lnx-2sinhx+2e^x-4tanx)

    thanks in advance for anyhelp

    another question if i have 2lnx is that the same as 2/x?

    For the chain rule you have two functions in it. For example for the first question the sin() is a function and whats in the brackets is another function. Differentiate them both and muliply

    1. sin(3e^x-2cosx+10e^x+2sinhx)

    Differentiate sin to get cos, Differentiate the stuff in the brackets to get 3e^x-2cosx+10e^x+2coshx (just diff each component in brcket). This is then muliplied out the front to get:

    (3e^x+2sinx+10e^x+2coshx)cos(3e^x-2cosx+10e^x+2sinhx)

    2. cos(3lnx-2sinhx+2e^x-4tanx)

    Differentiate cos to get -sin, Differentiate the stuff in the brackets to get (3/x)-2coshx+2e^x-4sec^2(x) (just diff each component in brcket). This is then muliplied out the front to get:

    [(3/x)-2coshx+2e^x-4sec^2(x)]*-sin(3lnx-2sinhx+2e^x-4tanx)

    3. THe differentiation of 2lnx is 2/x



    Does that help you?


  • Closed Accounts Posts: 96 ✭✭subzero12


    yeah it does thanks allot !
    i was just confusing myself here,its been 2 years since if covered this so im very rusty!


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