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    (x-y)^4 = x+y+5

    so far i have done :

    4 (x-y)^3 (1-dy/dx) = 1 + dy/dx



    and the answer is : 4(x-y)^3-1 / 1+4(x-y)^3

    How do i get to this answer step by step .
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    (Original post by charly2012)
    (x-y)^4 = x+y+5

    so far i have done :

    4 (x-y)^3 (1-dy/dx) = 1 + dy/dx



    and the answer is : 4(x-y)^3-1 / 1+4(x-y)^3

    How do i get to this answer step by step .
    Expand the left hand side - multiply all of 4(x-y)^3 by each term in the next bracket then proceed as normal.
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    didnt quite get to that weird answer
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    (Original post by charly2012)
    (x-y)^4 = x+y+5

    so far i have done :

    4 (x-y)^3 (1-dy/dx) = 1 + dy/dx



    and the answer is : 4(x-y)^3-1 / 1+4(x-y)^3

    How do i get to this answer step by step .
    There's no need to expand the (x-y)^3 brackets. You basically have:
    A(1 - dy/dx) = 1 + dy/dx which can be rewritten as:
    A - A(dy/dx) = 1 + dy/dx

    I'm sure you can rearrange this to get the dy/dx terms on 1 side
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    sorry i am not quite sure what the middle steps are , i been working through it in many way but didnt really get the similar answer . an answer would be much appreciated !
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    (Original post by charly2012)
    sorry i am not quite sure what the middle steps are , i been working through it in many way but didnt really get the similar answer . an answer would be much appreciated !
    post your working
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    my working is :

    4 (x-y)^3 (1-dy/dx) = 1 + dy/dx

    and i am not sure from here !
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    any clue or answer by any chance
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    (Original post by charly2012)
    any clue or answer by any chance
    Post 4 told you how to do this

    If you do not understand from that I think it would be best to ask your teacher
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    I didnt give up and tried to solve the problem : )

    Is it correct , and is this ho you approach it after the 1st step

    thanks .Name:  answer.png
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    ??
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    (Original post by charly2012)
    ??
    Yes that's right!

    You did the hard part which was the implicit differentiation - the rest was just rearranging an equation to get dy/dx on its own
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    Yea thank you for your hint , but to be honest i did not know you can multiply 4 (x-y)^3 BY (1-dy/dx)

    Is it always like that .
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    (Original post by charly2012)
    Yea thank you for your hint , but to be honest i did not know you can multiply 4 (x-y)^3 BY (1-dy/dx)

    Is it always like that .
    I think you need to take a step back and think about what you're asking

    dy/dx is just some function. (1-(dy/dx)) is just another function. You can multiply this by another function...why would you NOT be able to do this??


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    (Original post by davros)
    Yes that's right!

    You did the hard part which was the implicit differentiation - the rest was just rearranging an equation to get dy/dx on its own
    That is what I meant in the first reply albeit poorly worded. Oops.
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    (Original post by davros)
    I think you need to take a step back and think about what you're asking

    dy/dx is just some function. (1-(dy/dx)) is just another function. You can multiply this by another function...why would you NOT be able to do this??


    I am able to , but what i normally do is differentiate it and put dy/dx on one side and take it out and then do the division. but i was bit too slow in proccessing that question . thanks for the tips
 
 
 
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