According to the meaning of the question, the quadrilateral CDPE is a rectangle

∴PC=DE，

When PC is the smallest, DE is the smallest.

AB=√(AC^2+BC^2)= 10，

CH⊥AB over c is in h,

Then sδ ABC =1/2ac * BC =1/2ab * ch,

CH=8×6/ 10=4.8 .

∴DE minimum =CP minimum =CH=4.8.