问题 填空题
在极坐标系中,方程ρsin(θ-
π
4
)=
2
的直角坐标方程是______.
答案

ρsin(θ-

π
4
)=
2
,化为:ρsinθ-ρcosθ=2,方程ρsin(θ-
π
4
)=
2
的直角坐标方程是:x-y+2=0.

故答案为:x-y+2=0.

问答题

       在中国近现代史上,中国社会性质发生过三次变化。请你指出1949年—1956年底中国社会性质发生的两次变化?简要说明每次变化的主要原因是什么?

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                             

                                                                                                                                                              

                                                                                                                                                              

单项选择题 B1型题