5.设a,b∈R,a+bi=$\frac{11-7i}{1-2i}$,则a+b的值为( )
A. | 8 | B. | 9 | C. | 10 | D. | 12 |
1.已知等式$sin(θ+\frac{π}{6})=1-{log_{\frac{1}{2}}}x$,则x的取值范围是( )
A. | [1,4] | B. | $[{\frac{1}{4},1}]$ | C. | [2,4] | D. | $[{\frac{1}{4},4}]$ |
20.$\frac{7}{8}-\frac{7}{4}{sin^2}{15°}$的值等于( )
A. | $\frac{7}{8}$ | B. | $\frac{7}{16}$ | C. | $\frac{{7\sqrt{3}}}{8}$ | D. | $\frac{{7\sqrt{3}}}{16}$ |
19.设a=sin55°,b=cos55°,c=tan55°,则( )
A. | a>b>c | B. | b>c>a | C. | c>a>b | D. | c>b>a |
18.已知向量$\overrightarrow a=(1,1),\overrightarrow b=({x^2},x-2)$,若$\overrightarrow a⊥\overrightarrow b$,则实数x的值为( )
A. | -1 | B. | 2 | C. | 1或-2 | D. | -1或2 |
17.代数式sin120°cos240°的值为( )
0 251573 251581 251587 251591 251597 251599 251603 251609 251611 251617 251623 251627 251629 251633 251639 251641 251647 251651 251653 251657 251659 251663 251665 251667 251668 251669 251671 251672 251673 251675 251677 251681 251683 251687 251689 251693 251699 251701 251707 251711 251713 251717 251723 251729 251731 251737 251741 251743 251749 251753 251759 251767 266669
A. | $-\frac{3}{4}$ | B. | $-\frac{{\sqrt{3}}}{4}$ | C. | $-\frac{3}{2}$ | D. | $-\frac{1}{4}$ |