Question

R^2-r^2=Rr则r/R等于多少

Answer 1

解由R^2-r^2=Rr

两边除以R^2

即1-(r/R)^2=r/R

即(r/R)^2+r/R-1=0

令t=r/R

知t^2+t-1=0

即t=(1+√5)/2或t=(1-√5)/2

即r/R=(1+√5)/2或r/R=(1-√5)/2