数学方面的英文翻译:XXXX是与水平轴相交且交点处切线斜率为负的点

数学方面的英文翻译:XXXX是与水平轴相交且交点处切线斜率为负的点
RT。。
I want to know how to describe this sentence. Basically, I know the structure should be like, XXXX is equilibrim point that/wehre....
My English knowledge in Mathetics is rather less. I am not able to say it precisely.
Thanks all possible helpers in advance.