Let a=i+xj+k ,b=i+j+k, and |a+b |= |a |+ |b | then

Question

Accepted Answer

Correct answer: A. (a) Given a=i+xj+k and b=i+j+k with |a+b |= |a |+ |b | Take, |a+b |= |a |+ |b | |i+xj+k+i+j+k |= 1+x^2+1+ 1+1+1 |2i+ (x+1 )j+2k |= x^2+2+ 3 4+x^2+1+2x+4= x^2+2+ 3 x^2+2x+4= x^2+2+ 3 Take square both sides. x^2+2x+9=x^2+2+3+ 3(x^2+2)2x+9-5=2 3(x^2+2) (x+2 )= 3(x^2+2) Take square both sides, x^2+4+4x=3x^2+6 (x-1 )^2=0 ⇒x=1

$Let a = i + x j + k, b = i + j + k, and | a + b | = | a | + | b | then$

Solution

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