③函數(shù)的圖象關(guān)于點對稱;
②若,且;
15.關(guān)于函數(shù),有下列命題:
①由f (x1) = f (x2)=0可得x1-x2必是π的整數(shù)倍;
14.已知集合,
M∩N的子集的個數(shù)為4,則實數(shù)a的取值范圍是 .
13.已知如圖數(shù)表中的數(shù)滿足:(1)第n行首尾兩數(shù)均為n;
(2)每一行除首尾兩數(shù)外,中間任一數(shù)等于它肩上兩數(shù)
之和.則第n行(n≥2)第2個數(shù)an= .
11.已知,坐標(biāo)原點O在直線AB上的射影為點C,則 .
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