JEE Main20246 Apr 2024Evening ShiftMathematicsVector AlgebraActual

Let a =2 i + j - k , b =(( a ( i + j )) i ) i . Then the square of the projection of a on b is :

Options

A1 3
B2 3
C2
D1 5

Correct answer

C. 2

Step-by-step solution

aligned & a ( i + j )= | array ccc i & j & k 2 & 1 & -1 1 & 1 & 0 array | & = i - j + k & ( a ( i j )) i = k + j & (( a ( i j )) i) i = j - k & projection of a on b = a b | b | & = 1+1 2 = 2 aligned

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