解：|a|=2,|b|=3. |a-b|=√(a-b)^2 =√(a^2-2ab+b^2). =√(2^2-2|a||b|cos+b^2). =√(4-2*2*3*cos60°+3^2). =√(4-6+9). =√7. |a-2b|=√[a^2-2a*2b+(2b)^2]. =√(a^2-2*2ab+4b^2). =√(a^2-2*2|a||b|cos+4b^2). =√[4-4*2*3*(1/2)+4^9]. =√28. =2√7.
