Q. Find the 2nd term in the expansion of (x+8y)4 in simplest form.Answer:
Use Binomial Theorem: To find the 2nd term in the expansion of (x+8y)4, we will use the binomial theorem. The general form of the k-th term in the expansion of (a+b)n is given by T(k)=C(n,k−1)⋅a(n−k+1)⋅b(k−1), where C(n,k) is the binomial coefficient "n choose k". For the 2nd term, k=2.
Calculate Binomial Coefficient: We calculate the binomial coefficient for the 2nd term, which is C(4,2−1)=C(4,1). The binomial coefficient C(n,k) can be calculated as k!⋅(n−k)!n!, where “!“ denotes factorial.
Correct Calculation: Now we calculate C(4,1)=(1!∗(4−1)!)4!=(1∗3!)4=(1∗6)4=64=32. However, this is a mistake because C(4,1) should be calculated as (1!∗(4−1)!)4!=(1∗3!)4=(1∗6)4=64=32, which simplifies to 4, not 32.
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