15.曲线f(x)=x3+x-2在点P处的切线平行于直线4x-y-1=0,则点P的坐标为( )
| A. | (1,0) | B. | (2,8) | C. | (1,0)或(-1,-4) | D. | (2,8)或(-1,-4) |
14.若双曲线$\frac{{x}^{2}}{{a}^{2}}$-$\frac{{y}^{2}}{3}$=1(a>0)的离心率为2,则a等于( )
| A. | 2 | B. | $\sqrt{3}$ | C. | $\frac{3}{2}$ | D. | 1 |
13.函数y=x2(x-3)的单调递减区间是( )
| A. | (-∞,0) | B. | (2,+∞) | C. | (0,2) | D. | (-2,2) |
12.命题“?x0∈∁RQ,x03∈Q”的否定是( )
| A. | ?x0∉∁RQ,x03∈Q | B. | ?x0∈∁RQ,x03∈Q | C. | ?x∉∁RQ,x3∈Q | D. | ?x∈∁RQ,x3∉Q |
11.下列不等式一定成立的是( )
| A. | lg(x2+$\frac{1}{4}$)>lgx(x>0) | B. | sin x+$\frac{1}{sinx}$≥2(x≠$\frac{kπ}{2}$,k∈Z) | ||
| C. | x2+1≥2|x|(x∈R) | D. | $\frac{1}{{x}^{2}+1}$>1(x∈R) |
10.若Sn=sin$\frac{π}{7}+sin\frac{2π}{7}+…+sin\frac{nπ}{7}(n∈{N^*})$,则在S1,S2,…,S2017中,正数的个数是( )
| A. | 143 | B. | 286 | C. | 1731 | D. | 2000 |
9.已知斜率为3的直线l与双曲线C:$\frac{x^2}{a^2}-\frac{y^2}{b^2}$=1(a>0,b>0)交于A,B两点,若点P(6,2)是AB的中点,则双曲线C的离心率等于( )
0 235002 235010 235016 235020 235026 235028 235032 235038 235040 235046 235052 235056 235058 235062 235068 235070 235076 235080 235082 235086 235088 235092 235094 235096 235097 235098 235100 235101 235102 235104 235106 235110 235112 235116 235118 235122 235128 235130 235136 235140 235142 235146 235152 235158 235160 235166 235170 235172 235178 235182 235188 235196 266669
| A. | $\sqrt{2}$ | B. | $\sqrt{3}$ | C. | 2 | D. | $2\sqrt{2}$ |