If the vectors vec(P)=ahat(i) + ahat(j) + 3hat(k) and vec(Q)=ahat(i) -2hat(j) - hat(k) are perpendicular to each other, then positive value of a is :

If the vectors vec(P)=ahat(i) + ahat(j) + 3hat(k) and vec(Q)=ahat(i) -

1.	If the vectors vec(P)=ahat(i) + ahat(j) + 3hat(k) and vec(Q)=ahat(i) -2hat(j) - hat(k) are perpendicular to each other, then positive value of a is :
Answer» 3 2 1 zero Solution :Here `VEC(P)=AHATI+ahatj +3hatk, vec(Q)=ahati-2hatj-hatk` Dot PRODUCT of `bot` rvector is zero i.e., `vec(P).vec(Q)=0` `(ahati + ahatj +3hatk)-(ahati-2hatj-hatk)=0` `a^(2)-2a-3=0` a(a-2)=3 when a = 3 only then a - 2 is positive.

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If the vectors vec(P)=ahat(i) + ahat(j) + 3hat(k) and vec(Q)=ahat(i) -2hat(j) - hat(k) are perpendicular to each other, then positive value of a is :

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