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    I came across this question in my textbook and have absolutely no idea how to approach 4b. I've attached the image and any help would be really appreciated!
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    (Original post by maisym00)
    I came across this question in my textbook and have absolutely no idea how to approach 4b. I've attached the image and any help would be really appreciated!
    Should be in whatever formula booklet your exam board uses..you just want the general term of the binomial expansion
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    (Original post by maisym00)
    I came across this question in my textbook and have absolutely no idea how to approach 4b. I've attached the image and any help would be really appreciated!
    Write out the first 3 or 4 terms and try and see a general pattern. If you can't see it write out a few more.
    Just try and find a general pattern.
    This would be easy if the exponent was a positive integer - but as it isn't yu cannot use the ' nCr ' pattern.

     \displaystyle \left (1-\frac{x}{10} \right )^{-3} = 1+(-3) \left (-\frac{x}{10} \right ) + (-3)(-4) \left (-\frac{x}{10} \right )^2 \left (\frac{1}{2!} \right )+ \cdots .
 
 
 
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