the general term is
GT(n+1) = C(10,n)(x^2)^n (3)^(10-n)
= C(10,n)(x)^2n (3)^(10-n)
so the x^16 has to come from the x^2n
and 2n = 16
n = 8
so it is term(9) and it is
C(10,9)(x^2)^8 (3)^(10-8)
= 10(x^16)(9)
= 90x^16
so the coefficient is 90
in the expansion of (x^2+3)^10 what is the coefficient of the term containing x^16. I did 10c4 * 3. But i am not getting the correct answer. can someone please show me how to do this. thanks for your time!
3 answers
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so it is term(9) and it is
C(10,9)(x^2)^8 (3)^(10-8)
= 10(x^16)(9)
= 90x^16
so the coefficient is 90 >>
should have said:
so it is term(9) and it is
C(10,8)(x^2)^8 (3)^(10-8)
= 45(x^16)(9)
= 405x^16
so the coefficient is 405
so it is term(9) and it is
C(10,9)(x^2)^8 (3)^(10-8)
= 10(x^16)(9)
= 90x^16
so the coefficient is 90 >>
should have said:
so it is term(9) and it is
C(10,8)(x^2)^8 (3)^(10-8)
= 45(x^16)(9)
= 405x^16
so the coefficient is 405
thanks!