Explain solution for RD Sharma maths class 12 chapter 22 Algebra of vectors exercise 22.8 question 9 maths textbook solution
Answer: Vectors are coplanar
Hint: Prove and express that vectors can be coplanar if we can express them as the linear combination.
Given, three vectors & to be proved as coplanar
Now “Necessary condition”
To be coplanar vectors must be expressed as linear combination of other two.
If & has to be coplanar.
There exists, .....(1)
Where x and y be some scalars.
Hence, ....(2)
Comparing (1) and (2)
We can say, l=x
m = y
c = -1
For to be coplanar they must satisfy this.Wherel,m and n are non-zero simultaneously.
“Sufficient Condition”
If we suppose that & be three vectors satisfying
Where l,m and n not all zero simultaneously as scalars.
So from,
Thus, can be written as linear combination of & where and be some scalars.
Hence, & are coplanar vectors.