17.函数y=$\sqrt{1-{x}^{2}}$的值域是( )
| A. | (2,3) | B. | [0,1] | C. | [0,+∞) | D. | (-∞,1] |
14.已知函数f(x)=$\left\{\begin{array}{l}{2x,x≤0}\\{f(x-3),x>0}\end{array}\right.$,则f(2016)=( )
| A. | 1 | B. | 2 | C. | 3 | D. | 0 |
13.
正方体中,BD1与B1C所成角是( )
| A. | 30° | B. | 45° | C. | 60° | D. | 90° |
12.已知直线a,b与平面α,则下列正确的命题是( )
①若a∥b,b?α,则a∥α;
②若a∥α,b∥α,则a∥b;
③若a∥α,b?α,则a∥b;
④a⊥α,b∥α,则a⊥b.
①若a∥b,b?α,则a∥α;
②若a∥α,b∥α,则a∥b;
③若a∥α,b?α,则a∥b;
④a⊥α,b∥α,则a⊥b.
| A. | ①④ | B. | ②④ | C. | ①③ | D. | ④ |
11.正方体中,EC与BD所成角是( )

0 231481 231489 231495 231499 231505 231507 231511 231517 231519 231525 231531 231535 231537 231541 231547 231549 231555 231559 231561 231565 231567 231571 231573 231575 231576 231577 231579 231580 231581 231583 231585 231589 231591 231595 231597 231601 231607 231609 231615 231619 231621 231625 231631 231637 231639 231645 231649 231651 231657 231661 231667 231675 266669
| A. | 30° | B. | 45° | C. | 60° | D. | 90° |