$($a$)$ Use the definition of scalar product a$.$b $=$ ab cos$\backslash$theta to calculate the angle between the

vectors a $=3$i $+2$j and b $=3$i $-4$j$.$ Both the vectors a and b are on the x$-$y plane.

$($b$)$ Three vectors are given by a $=3\mathrm{.}0$ i $+3\mathrm{.}0$ j $-2\mathrm{.}0$ k

b $=-1\mathrm{.}0$ i $-4\mathrm{.}0$ j $+2\mathrm{.}0$ k

c $=2\mathrm{.}0$ i $+2\mathrm{.}0$ j $+1\mathrm{.}0$ k

Compute a $.($ b $\backslash$times c $)$