对数有意义,真数>0
x-3>0 x>3
分式有意义,分母≠0
x+2≠0 x≠-2
综上,得x>3,函数的定义域为(3,+∞)
f(4)=log2(4-3) +1/(4+2)=0+1/6=1/6
f(7/2)=log2(7/2 -3)+1/(7/2 +2)=log2(1/2)+ 2/11=-1 +2/11=-9/11