binomial therom (1 Viewer)

cos16mh

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Can I have assistance for this question please

The expansion of (1+an)^n is given by 1-24x+252x^2-...Find values for a and n

Could you please explain how to do this thanks
 

integral95

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Can I have assistance for this question please

The expansion of (1+an)^n is given by 1-24x+252x^2-...Find values for a and n

Could you please explain how to do this thanks
I think you mistyped it and meant
 

integral95

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Can I have assistance for this question please

The expansion of (1+an)^n is given by 1-24x+252x^2-...Find values for a and n

Could you please explain how to do this thanks
Expanding the first 3 terms using Binomial thereom gives



Equate the co-efficient with last 2 terms to get a set of simultaneous equations to solve.




I got n = 8 and a = -3
 
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cos16mh

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ThANKS
Could you explain how the simultaneous equations worked please
 

integral95

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Could you explain how the simultaneous equations worked please
Substitution method, make a the subject in the first equation.



Sub that into the 2nd equation to get



In case you're confused, this is because





After simplifying and solving that equation you get n = 8 then sub it back to the first equation to get a = -3
 

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