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Unsure on how to answer these questions (binomial expansion c4) Watch

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    The questions in particular are 3 and 6
    Im not sure how you solve these as normally
    The expansion isn't multiplied by another value . I had thought i needed to multiply first or multiply the end result by whats before it however im not getting any right answers.

    How exactly do you solve these questions
    To note I can do something like
    First few terms of 7x+12/(x+3)(x+4) or (1+x/4)^1/2
    But not
    (x+1)(1+x/4)^1/2
    What exactly do you need to do ?
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    Expand and then multiply.
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    (Original post by Vanetti)
    Name:  DSC_0007.jpg
Views: 76
Size:  495.1 KB
    The questions in particular are 3 and 6
    Im not sure how you solve these as normally
    The expansion isn't multiplied by another value . I had thought i needed to multiply first or multiply the end result by whats before it however im not getting any right answers.

    How exactly do you solve these questions
    To note I can do something like
    First few terms of 7x+12/(x+3)(x+4) or (1+x/4)^1/2
    But not
    (x+1)(1+x/4)^1/2
    What exactly do you need to do ?
    Have you got any working out to show? Because I would work out the binomial expansion then multiply by (1+x) for question 3 but you said that you dont get the correct answer?

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    (Original post by Vanetti)
    Name:  DSC_0007.jpg
Views: 76
Size:  495.1 KB
    The questions in particular are 3 and 6
    Im not sure how you solve these as normally
    The expansion isn't multiplied by another value . I had thought i needed to multiply first or multiply the end result by whats before it however im not getting any right answers.

    How exactly do you solve these questions
    To note I can do something like
    First few terms of 7x+12/(x+3)(x+4) or (1+x/4)^1/2
    But not
    (x+1)(1+x/4)^1/2
    What exactly do you need to do ?
    (x+1)(1+x/4)^1/2 = (x+1)(1 + x/8 - x^2/128 + x^3/1024 - ...) using the binomial expansion,
    and now multiply out as x + x^2/8 - x^3/128 + x^4/1024 - ... + 1 + x/8 - x^2/128 + x^3/1024 - ...
    = 1 + 9x/8 + 15x^2/128 - 7x^3/1024 + ...
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    (Original post by HFancy1997)
    Have you got any working out to show? Because I would work out the binomial expansion then multiply by (1+x) for question 3 but you said that you dont get the correct answer?

    Posted from TSR Mobile
    Turns out I did have the correct answer but had an extra
    -4x^4 which I didn't realize the question had said in ascending powers of x (so that value isn't needed) thanks for the help I had thought I needed some random method or something
 
 
 
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