3.若$\sqrt{{a}^{2}}$=($\sqrt{a}$)2,则a的取值范围是( )
| A. | a>0 | B. | a≥0 | C. | a=0 | D. | a<0 |
2.在校田径运动会上,小明和其他三名选手参加100米预赛,赛场共设1,2,3,4四条跑道,选手以随机抽签的方式决定各自的跑道.若小明首先抽签,则小明抽到1号跑道的概率是( )
0 284434 284442 284448 284452 284458 284460 284464 284470 284472 284478 284484 284488 284490 284494 284500 284502 284508 284512 284514 284518 284520 284524 284526 284528 284529 284530 284532 284533 284534 284536 284538 284542 284544 284548 284550 284554 284560 284562 284568 284572 284574 284578 284584 284590 284592 284598 284602 284604 284610 284614 284620 284628 366461
| A. | $\frac{1}{16}$ | B. | $\frac{1}{4}$ | C. | $\frac{1}{3}$ | D. | $\frac{1}{2}$ |