Direction Ratios Of A Line Passing Through Two Points

Question 1

Let l, m, n be the direction cosines of the line PQ and let it makes angles α, β and γ with the x, y and z-axis direction cosines are
P(x1,y1,z1) Q(x2,y2,z2)

Answer 1

Cos a=l=x2-x1/PQ
Cos b=m=y2-y1/PQ
Cos g=n=z2-z1/PQ

Question 2

Let l, m, n be the direction cosines of the line PQ and let it makes angles α, β and γ with the x, y and z-axis direction cosines are
P(x1,y1,z1) Q(x2,y2,z2)

Answer 2

Cos a=l=x2-x1/PQ
Cos b=m=y2-y1/PQ
Cos g=n=z2-z1/PQ

Question 3

Let l, m, n be the direction cosines of the line PQ and let it makes angles α, β and γ with the x, y and z-axis direction ratios are
P(x1,y1,z1) Q(x2,y2,z2)

Answer 3

a=x2-x1
b=y2-y1
c=z2-z1

Question 4

Let l, m, n be the direction cosines of the line PQ and let it makes angles α, β and γ with the x, y and z-axis PQ is
P(x1,y1,z1) Q(x2,y2,z2)

Answer 4

PQ= sqrt(x2 −x1)^2 +(y2−y1)^2+(z2−z1)^2