由相似三角形得:
1.AB/A'B' =u/v
2.co/A'B' = f/(v-f)
3.AB = co
==>>
1.AB/A'B' = f/(v-f) = u/v
2.fv = uv-uf
3.u*v*f !=0
==>>
1/u + 1/v = 1/f
由相似三角形得:
1.AB/A'B' =u/v
2.co/A'B' = f/(v-f)
3.AB = co
==>>
1.AB/A'B' = f/(v-f) = u/v
2.fv = uv-uf
3.u*v*f !=0
==>>
1/u + 1/v = 1/f