斜率k=m/(1+m²).
∵|m/(1+m²)| (取绝对值)
=|m|/(1+m²)
=1/[|m|+(1/|m|)] (分子、分母同除|m|)
≤1/2.(利用均值不等式)
∴-1/2≤k≤1/2.
k=m/(1+m²)去分母整理得:
km²-m+k=0
关于m的二次方程判别式=1-4k²≥0即k²≤1/4,解得:-1/2≤k≤1/2.
斜率k=m/(1+m²).
∵|m/(1+m²)| (取绝对值)
=|m|/(1+m²)
=1/[|m|+(1/|m|)] (分子、分母同除|m|)
≤1/2.(利用均值不等式)
∴-1/2≤k≤1/2.
k=m/(1+m²)去分母整理得:
km²-m+k=0
关于m的二次方程判别式=1-4k²≥0即k²≤1/4,解得:-1/2≤k≤1/2.