Question

if |a|=2,|b|=3,(a.b)=
$120 {}^{0}$
then a.b?


​

Answer 1

Answer:

ab= 6

Step-by-step explanation:

if a=2 and b= 3

then ab= a×b

= 3×2

=6

Answer 2

❥︎ANSWER

Given, a+b+c=0

and ∣a∣=5,∣b∣=3,∣c∣=7

⇒a+b=c

On squaring both sides, we get

(a+b)2=(−c)2

⇒∣a+b∣2=∣c∣2

⇒∣a∣2+∣b∣2+2a⋅b=∣c∣2

(∵θ be the angle between a and b)

⇒(5)2+(3)2+2∣a∣∣b∣cosθ=(7)2

⇒25+9+2⋅5⋅3cosθ=49

⇒30cosθ=15

⇒cosθ=21=cos60∘

⇒θ=3π

❥︎THANKS

I hope it will help you.