Here, f: A—>B

f(x)= (x-1)/(x+2)  ;  x   -2 

A= {-1,0,1,2,3,4}

B= {-2,1,-1/2,0,1/2,1/4,2/5}

Range = {-2,-1/2,0,1/4,1/2,2/5}

As range is not equal to codomain so the given function is not bijective. 

We can make it bijective by omitting {1} from set B 

Yes, if the angle between the two vectors is more than 90^o but less than 270⁰. (cosΘ is negative)

No, if three vectors do not lie in a plane, they cannot give zero resultant.

Explanation:

Let A, B and C be three vectors. If they give zero resultant, then

     A+B+C=0

or, A= -(B+C)

Hence, they will produce zero resultant, if A is equal to negative of vector (B+C). The vector (B+C) lies in the plane of B and C. Hence, A will be equal to negative of (B+C) if A, B and C all lie in a plane.

There is, for sure, effect of gravity on fire. We know for a fact that fires on Earth are "pointy" while those in zero-gravity are "round". This is because fire is simply glowing gas. Gas is matter and matter has weight. For a body to have weight, gravity must influence it in some way.