4.25^(1/x)=1000,1/x*lg4.25=3 1/x=3/lg4.25
0.00425^(1/y)=1000,1/y*lg0.00425=3,1/y=3/lg0.00425=3/(lg4.25-3)
1/x-1/y=3/lg4.25-3/(lg4.25-3)=-9/[lg4.25*(lg4.25-3)]
4.25^x=1000
1000^(1/x)=4.25-----①
0.00425^y=1000
1000^(1/y)=0.00425--------②
①÷②得
1000^(1/x-1/y)=4.25÷0.00425=1000=1000^1
1/x-1/y=1