①f(x)和g(x)在x=1处有相同切线则,f`(1)=g`(1),f(1)=g(1)即3+a=4,1+a=2+b解得a=1,b=0∴f(x)=x�0�6+x,g(x)=2x�0�5②F(x)=f(x)-mg(x)=x�0�6+x-m(2x�0�5)=x�0�6-2mx�0�5+x在[0.5,3]单调减∴F`(x)=3x�0�5-4mx+1≥0在[0.5,3]恒成立m≤(3x�0�5+1)/4x=3x/4 +1/(4x)设u=3x/4+1/(4x)≥2√[(3x/4)×(1/(4x))]=√3/2当且仅当3x/4=1/(4x)时取等号此时x=√3/3∴u在[0.5.√3/3]单调减,(√3/3,3]单调增且umin=√3/2要满足m≤u恒成立只需m≤umin=√3/2∴m∈(-∞,√3/2]