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How would you solve these questions? (FP2 Edexcel Exam questions) watch

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    (Original post by 10DannyRush)
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    What have you tried so far?
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    (Original post by 10DannyRush)
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    2. Multiply through by x^2(x+3)^2, get everything on one side, and fully factorise. Draw a rough sketch of what the factorised quartic looks like then deduce the answer from the sketch.

    3b. You can use the method of differences to deduce \displaystyle \sum_{r=1}^n r^3-(r-1)^3. Then make this equal to \displaystyle 3 \sum_{r=1}^n r^2 - 3 \sum_{r=1}^n r - \sum_{r=1}^n 1.

    You know the latter two sums in terms of n, so just rearrange for \displaystyle \sum_{r=1}^n r^2
 
 
 
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