变式训练,一解多题,能以一挡十,有效提高学习效率.现以an+1=pan+f(n)型递推数列为例,通过变换题目条件,以掌握一类递推数列通项的求法.一、an+1=an+f(n)型(1)当f(n)=常数,则数列{an}为等差数列,得an=a1+(n-1)d.(2)当f(n)≠常数,若f(n)可求和,则可 Variant training, a solution of multiple questions, with a block of ten, effectively improve the learning efficiency. Now an + 1 = pan + f (n) recursive sequence as an example, by changing the subject conditions, to grasp a class of recursion (1) When f (n) = constant, the sequence {an} is an arithmetic sequence with an = a1 + (n-1) d (2) When f (n) ≠ constant, f (n) can be summed