【简答题】在平面直角坐标系xOy中,曲线y=x -6x+1与坐标轴的交点都在圆C上. (Ⅰ)求圆C的方程; (Ⅱ)试判断是否存在斜率为1的直线,使其与圆C交于A, B两点,且OA⊥OB,若存在,求出该直线方程,若不存在,请说明理由.
【单选题】--- Jane, ________________________ --- A policeman.
B.
what does your brother do?
C.
where is your brother?
D.
how old is you brother?
【简答题】(坐标系与参数方程)在平面直角坐标系xOy中,点P的直角坐标为 (1,- 3 ) .若以原点O为极点,x轴正半轴为极轴建立极坐标系,则点P的极坐标可以是______.
【单选题】—____ ? —He is tall and thin.
A.
What does your brother do
B.
Hoe old is your brother
C.
What does your brother look like
【判断题】晶体管特性曲线分成三个区域: 放大区 、 截止区 和 饱和区
【简答题】在平面直角坐标系xoy中,直线l的参数方程是 x= 3 + 1 2 t y=3+ 3 2 t (其中t为参数),以ox为极轴的极坐标系中,圆C的极坐标方程为ρ=cosθ,则圆心C到直线l的距离为______.
【单选题】坐标面xoy上的双曲线【图片】绕y轴旋转而成的曲面方程是( )
【简答题】选修4-4:坐标系与参数方程 以平面直角坐标系xoy的原点O为极点,x轴的正半轴为极轴建立极坐标系,直线l的极坐标方程为 ρcos(θ+ π 4 )+ 2 =0 ,曲线C 1 的参数方程为 x=2+4cosθ y= 1 2 +sinθ (θ是参数) (1)若把曲线C 1 上的横坐标缩短为原来的 1 4 ,纵坐标不变,得到曲线C 2 ,求曲线C 2 在直角坐标系下的方程 (2)在第(1)问的条件下,...
【单选题】3*85.可以满足某一特定性别,年龄及生理状况群体中绝大多数个体(97-98%)需要量的某种营养素摄入水平是
【单选题】_______? ----He is very kind to us.
A.
What does your brother look like
B.
How is your brother C What do you think of your brother D. How much do you like your brother