1.求下列直线的夹角:
(1)y=6x+7,y=-1/6x-5;
(2)y=x-5,x=1;
(3)x-2y-4=0,y=3x+2;
(4)3x-根号3y+10=0,
根号3x+y+8=0.
1.求下列直线的夹角:
(1)y=6x+7,y=-1/6x-5;
(2)y=x-5,x=1;
(3)x-2y-4=0,y=3x+2;
(4)3x-根号3y+10=0,
根号3x+y+8=0.
(1) k1=6,k2=-1/6,k1k2=-1,两直线互相垂直,所以θ=π/2;
(2) k1=1,与x轴夹角π/4,k2不存在,与x轴夹角π/2,所以θ=π/2-π/4=π/4;
(3) k1=1/2,k2=3,tanθ=|(k2-k1)//(1+k1k2)|=|(3-1/2)/(1+3*1/2)=1,∴θ=π/4;
(4) k1=√3,k2=-√3,tanθ=|(k2-k1)//(1+k1k2)|=|(-√3-√3)/(1-√3*√3)|=√3,∴θ=π/3.