Question

Find the direction cosines of the line joining the points(2,0,0)and (0,2,2)​

Answer 1

Answer:

If we have two points P(x

1

,y

1

,z

1

) and Q(x

2

,y

2

,z

2

),then the dc’s of the line segment joining these two points are

PQ

(x

2

−x

1

)

,

PQ

(y

2

−y

1

)

,

PQ

(z

2

−z

1

)

The distance between given points=

(4−2)

2

+(1−0)

2

+(1−3)

2

=3

⇒ the directional cosines =

3

(4−2)

,

3

(1−0)

,

3

(1−3)

⇒ dc's =

3

2

,

3

1

,

3

−2