问题描述: a=(λ,2),b=(3,5)且a与b夹角θ∈【π/3,2π/3】则λ取值范围 1个回答 分类:数学 2014-12-07 问题解答: 我来补答 设b=(3,5)与X轴夹角为xx=arctan(5/3)则tan[arctan(5/3)+π/3]={tan[arctan(5/3)]+tan(π/3)}/{1-tan[arctan(5/3)]tan(π/3)}=[5/3+根号3]/[1-5/3*根号3]=-(30+17根号3)/33λ=-60+34根号3tan[arctan(5/3)+2π/3]={tan[arctan(5/3)]+tan(2π/3)}/{1-tan[arctan(5/3)]tan(2π/3)}=[5/3-根号3]/[1+5/3*根号3]=(-30+17根号3)/33λ=-60-34根号3所以λ∈【-60-34根号3,-60+34根号3】 展开全文阅读