【单选题】若二项式(x+2) n 的展开式的第四项是 4 2 ,而第三项的二项式系数是14,则x的值为( )
【简答题】若 ( 6 x + 1 6 x ) n 展开式中第二、三、四项的二项式系数成等差数列. (1)求n的值; (2)此展开式中是否有常数项,为什么?
【简答题】听音,选择恰当的答语。 ( )1. A. Fine, thank you! B. Good morning! ( ) 2. A. Good afternoon ! B. Good morning! ( )3. A. My name is Sarah. B. Let's play. ( )4. A. Here you are. B. Here it is. ( ...
【简答题】听力原文:MAN: Good morning. Tuber Insurance Company. How can I help you? WOMAN: Good morning. I want to alter my insurance policy. MAN: Is that for your house, contents, or vehicle? WOMAN: My vehicle. The...
【简答题】观察下列等式(x 2 +x+1) 0 =1,(x 2 +x+1) 1 =x 2 +x+1,(x 2 +x+1) 2 =x 4 +2x 3 +3x 2 +2x+1,(x 2 +x+1) 3 =x 6 +3x 5 +6x 4 +7x 3 +6x 2 +3x+1… 可以推测(x 2 +x+1) 5 展开式中各项系数的和为______.第四、五、六项系数的和是______.
【简答题】有以下四个命题: ①4名同学分别报名参加学校组织的数学、物理、化学三个项目的竞赛,每人限报其中的一项,不同报法的种数是4 3 ; ②4名同学分3张有座足球票,每人至多分l张,而且必须分完,那么不同分法的种数是C 4 3 ; ③从含有98件正品,2件次品的100件产品中任意抽取3件,抽取的这3件产品中至少有l件次品的概率是 C 12 C 299 C 3100 ; ④在(1-x) 2n+1 (n∈N ...
【单选题】Clerk:Good mornin9,Madam?Censumer:__________.I‘d like to open a savings account.
【单选题】—______. can you help me with my homework? — All right.
【单选题】—Hi,Alice ! Good afternoon! —________.A. Hi; Good afternoon B. Thank you; Good mornin
A.
4.—Hi,Alice ! Good afternoon! —________. A. Hi; Good afternoon
B.
Thank you; Good morning
【简答题】根据所给情景,选择最佳答语,补全对话。 ( ) 1. Good morning, Miss Li! A. Good. B. Good bye! C. Good morning. ( ) 2. Hi! My name is Li Tao. What's your name? A. My name is Tom. B. What's your name? C. I don't know...