Question

（1+2x）⁸的展開式中第四項(xiàng)的二項(xiàng)式系數(shù)是

1. A.
   C₈³
2. B.
   C₈⁴
3. C.
   C₈³•2³
4. D.
   C₈⁴•2⁴

Answer 1

A
分析：直接根據(jù)二項(xiàng)展開式的性質(zhì)，各項(xiàng)二項(xiàng)式系數(shù)C₈⁰，C₈¹，C₈²，C₈³，…C₈⁸，得到所求選項(xiàng)．
解答：根據(jù)項(xiàng)的二項(xiàng)式系數(shù)的定義可知，二項(xiàng)式各項(xiàng)二項(xiàng)式系數(shù)為：C₈⁰，C₈¹，C₈²，C₈³，…C₈⁸，所以（1+2x）⁸的展開式中第四項(xiàng)的二項(xiàng)式系數(shù)是C₈³．
故選A．
點(diǎn)評(píng)：本題是基礎(chǔ)題，考查二項(xiàng)展開式二項(xiàng)式系數(shù)的計(jì)算，注意二項(xiàng)展開式項(xiàng)的系數(shù)與二項(xiàng)式系數(shù)的區(qū)別．