4.
如图,两同心圆的圆心为O,大圆的弦AB与小圆相切于点P,已知两圆的半径分别为2和1,用阴影部分围成一个圆锥(OA与OB重合),则该圆锥的底面半径是( )
| A. | $\frac{3}{4}$ | B. | $\frac{4}{3}$ | C. | $\frac{2}{3}$ | D. | $\frac{3}{2}$ |
2.正比例函数的图象经过点(-1,2),则这个图象必须经过点( )
| A. | (-2,1) | B. | (2,-1) | C. | (1,-2) | D. | (1,2) |
20.如图所示的四个几何体,其中左视图与俯视图相同的几何体共有几个( )
| A. | 1 | B. | 2 | C. | 3 | D. | 4 |
19.使$\sqrt{2x-10}$有意义的x的取值范围是( )
| A. | x>5 | B. | x≥5 | C. | x≠5 | D. | 全体实数 |
18.计算a12÷a4(a≠0)的结果是( )
0 294222 294230 294236 294240 294246 294248 294252 294258 294260 294266 294272 294276 294278 294282 294288 294290 294296 294300 294302 294306 294308 294312 294314 294316 294317 294318 294320 294321 294322 294324 294326 294330 294332 294336 294338 294342 294348 294350 294356 294360 294362 294366 294372 294378 294380 294386 294390 294392 294398 294402 294408 294416 366461
| A. | a3 | B. | a-8 | C. | a8 | D. | a-3 |