2.若复数(a2-1)+(a-1)i是纯虚数,则实数a的值为( )
A. | 1 | B. | 0 | C. | 1或-1 | D. | -1 |
14.已知函数$f(x)=\left\{\begin{array}{l}m{x^2}-8ax+n,x<1\\ log_a^x\begin{array}{l}{\begin{array}{l},{x≥1}\end{array}}\end{array}\end{array}\right.$,其中m为函数$g(x)=2x+\sqrt{x-1}$的最小值,n为函数$h(x)={3^{1-{x^2}}}$的最大值,且对任意x1≠x2,都有$\frac{{f({x_2})-f({x_1})}}{{{x_1}-{x_2}}}>0$成立,则实数a的取值范围是( )
A. | $(0,\frac{1}{2}]$ | B. | (1,2] | C. | $[\frac{5}{8},1)$ | D. | $[\frac{1}{2},\frac{5}{8}]$ |
13.已知a=log3650.99、b=1.01365、c=0.99365,则a、b、c的大小关系为( )
0 252377 252385 252391 252395 252401 252403 252407 252413 252415 252421 252427 252431 252433 252437 252443 252445 252451 252455 252457 252461 252463 252467 252469 252471 252472 252473 252475 252476 252477 252479 252481 252485 252487 252491 252493 252497 252503 252505 252511 252515 252517 252521 252527 252533 252535 252541 252545 252547 252553 252557 252563 252571 266669
A. | a<c<b | B. | b<a<c | C. | a<b<c | D. | b<c<a |