Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NDA2012MathematicsVector AlgebraActual

What is the value of for which ( i + j - k ) (3 i -2 j +4 k )=(2 i -11 j -7 k ) ?

Options

  1. A2
  2. B-2
  3. C1
  4. D7

Correct answer

A. 2

Step-by-step solution

( i + j -k) (3 i -2 j +4 k)=2 i -11 j -7 k | array ccc i & j & k & 1 & -1 3 & -2 & 4 array |=2 i -11 j -7 k i (4-2)- j (4 +3)+ k (-2 -3)=2 i -11 j -7 k from above 4 +3=11 =2 .

Practice Vector Algebra on Quantrex Academy →

More from Vector Algebra

Passage: Let a b = c and b c = a . Question: Consider the following statements : I. ( a b ) c +( b c ) a =( c a ) b II. ( a b ) ( b c ) b =1 Which of the statements given above is/ 2026Passage: Let a , b , c , a + b , b + c , a + b + c be unit vectors. Question: What is the angle between a and b ? 2026Passage: Let a , b , c be unit vectors. Further, a is perpendicular to b ; c makes an angle 3 with both a and b ; and c =p a +q b +r( a b ) . Question: What is the value of r^2 ? 2026Passage: Let a , b , c , a + b , b + c , a + b + c be unit vectors. Question: What is the angle between a and c ? 2026Passage: Let a b = c and b c = a . Question: Consider the following statements : I. a , b , c are orthogonal in pairs. II. a , b , c are unit vectors. Which of the statements given 2026Passage: Let a , b , c be unit vectors. Further, a is perpendicular to b ; c makes an angle 3 with both a and b ; and c =p a +q b +r( a b ) . Question: What is the value of (p+q) ? 2026What is the area of the parallelogram whose sides are represented by the vectors i + 2 j + 3 k and 2 i + j + 2 k ? 2025Let p = a - b , q = a + b . If | a | = | b | = 2 and a b = 2 , then what is the value of | p q | ? 2025 Full Vector Algebra list All NDA PYQs