题目内容
11.化简:(1-x)5+(x+1)5.分析 按照二项式定理把(1-x)5 和(x+1)5 分别展开,可得:(1-x)5+(x+1)5的结果.
解答 解:(1-x)5+(x+1)5 =${C}_{5}^{0}$-${C}_{5}^{1}$•x+${C}_{5}^{2}$•x2-${C}_{5}^{3}$•x3+${C}_{5}^{4}$•x4-${C}_{5}^{5}$•x5+${C}_{5}^{0}$+${C}_{5}^{1}$•x+${C}_{5}^{2}$•x2+${C}_{5}^{3}$•x3+${C}_{5}^{4}$•x4+${C}_{5}^{5}$x5
= 2${C}_{5}^{0}$+2${C}_{5}^{2}$•x2+2${C}_{5}^{4}$•x4=2+20x2+10x4.
点评 本题主要考查二项式定理的应用,二项式展开式的通项公式,属于基础题.
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