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C4 Binomial expansion + partial fractions

Need help on 2ci , im pretty sure ive messed up expanding it somewhere in my working but 51/2 isnt correct it should be 12
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Avatar for Zacken
Zacken
22
Original post by Mitul106
Need help on 2ci , im pretty sure ive messed up expanding it somewhere in my working but 51/2 isnt correct it should be 12


Thankfully, it's just a tiny arithmetical slip. When you expand out, the x3x^3 terms are:

−32x3−12(−27x3)=−3x32+272x3=12x3-\frac{3}{2}x^3 - \frac{1}{2}(-27x^3) = -\frac{3x^3}{2} + \frac{27}{2}x^3 = 12x^3 as required. Did you forget the negative signs?
Reply 2
Avatar for Mitul106
Mitul106
OP
10
Original post by Zacken
Thankfully, it's just a tiny arithmetical slip. When you expand out, the x3x^3 terms are:

−32x3−12(−27x3)=−3x32+272x3=12x3-\frac{3}{2}x^3 - \frac{1}{2}(-27x^3) = -\frac{3x^3}{2} + \frac{27}{2}x^3 = 12x^3 as required. Did you forget the negative signs?


Oh god im a moron lol i didnt put it over 2 in my calculator urghhhh aha

Thankyouu
Reply 3
Avatar for Zacken
Zacken
22
Original post by Mitul106
Oh god im a moron lol i didnt put it over 2 in my calculator urghhhh aha

Thankyouu


Awesome! No problem. :smile:

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