6.双曲线x2-4y2=4的两个焦点F1、F2,P是双曲线上的一点,满足PF1⊥PF2,则△F1PF2的面积为( )
| A. | 1 | B. | $\frac{\sqrt{5}}{2}$ | C. | 2 | D. | $\sqrt{5}$ |
4.设a+b=1,b>0,则$\frac{1}{2|a|}+\frac{|a|}{b}$的最小值为( )
| A. | $\sqrt{2}+\frac{1}{2}$ | B. | $\sqrt{2}-\frac{1}{2}$ | C. | $\frac{5}{4}$ | D. | $\frac{3}{4}$ |
3.在区间(1,2)上,不等式x2+mx+4>0有解,则m的取值范围为( )
| A. | m>-4 | B. | m<-4 | C. | m>-5 | D. | m<-5 |
1.已知菱形ABCD的边长为2,∠BAD=120°,$\overrightarrow{BE}=\frac{1}{2}\overrightarrow{BC}$,$\overrightarrow{DF}=\frac{1}{3}\overrightarrow{DC}$,则$\overrightarrow{AE}•\overrightarrow{AF}$=( )

| A. | $\frac{1}{2}$ | B. | 2 | C. | 1 | D. | $\frac{1}{6}$ |
20.设$sin(\frac{π}{4}+θ)=\frac{1}{3}$,则$cos(2θ+\frac{π}{2})$=( )
| A. | $\frac{7}{9}$ | B. | $\frac{1}{9}$ | C. | $-\frac{7}{9}$ | D. | $-\frac{1}{9}$ |
19.若复数z满足$\frac{{|{1+i}|}}{z}$=1-i,则复数z的共轭复数$\bar z$的虚部为( )
| A. | $-\frac{{\sqrt{2}}}{2}i$ | B. | $-\frac{{\sqrt{2}}}{2}$ | C. | $\frac{{\sqrt{2}}}{2}i$ | D. | $\frac{{\sqrt{2}}}{2}$ |
18.已知数列{an}满足$2{a_{n+1}}+{a_n}=3({n∈{N^*}})$,且a1=4,其前n项和为Sn,则满足不等式$|{{S_n}-n-2}|<\frac{1}{30}$的最小整数n是( )
0 233184 233192 233198 233202 233208 233210 233214 233220 233222 233228 233234 233238 233240 233244 233250 233252 233258 233262 233264 233268 233270 233274 233276 233278 233279 233280 233282 233283 233284 233286 233288 233292 233294 233298 233300 233304 233310 233312 233318 233322 233324 233328 233334 233340 233342 233348 233352 233354 233360 233364 233370 233378 266669
| A. | 5 | B. | 6 | C. | 7 | D. | 8 |