The vectors a→=i^+j^+mk^,b→=i^+j^+(m+1)k^ and c→=i^-j^+mk^ are coplanar, if m is equal to?
1
4
3
no value of m for which vectors are coplanar
Explanation for correct option
Given vector are
a→=i^+j^+mk^,b→=i^+j^+(m+1)k^ and c→=i^-j^+mk^
We know that isa→,b→ and c→ are co-planer then the determinant of coefficient matrix is 0
∴11m11m-11-1m=0⇒1m+m-1+1+m-1-1=0⇒2m-1+1-2m=0
Hence, option (D) is correct