Find unit vectors that satisfy the given conditions:

1. The unit vector in the same direction as $\left<-3,1\right>$ is . help (vectors)
   
   
2. The unit vector oppositely directed to $-3\boldsymbol{i}+3\boldsymbol{j}+5\boldsymbol{k}$ is .
   
   
3. The unit vector that has the same direction as the vector from the point $A=\left(0,-3\right)$ to the point $B=\left(2,-4\right)$ is .