6.28r乘r+6.28r乘4=12.56怎么解?

问题描述:

6.28r乘r+6.28r乘4=12.56怎么解?

6.28r乘r+6.28r乘4=12.56 6.28乘(r乘r+4r)=12.56 r乘r+4r=2 r乘r+4r+4=6 (r+2)(r+2)=6 ±r+2=根号6 r=根号6+2 或 根号6-2