Question

if vector a is equals to vector b minus vector c then find the angle between vector a and vector b​

Answer 1

Simple, the angle between the 2 vectors is 0 degree.

First a+b= c

=>(a^2+b^2+2abcos(theta))^(1/2)=| c|

where theta is the angle between a and b.

Again a+b=c

=> (a+b)^2=c^2=| c |^2=a^2+b^2+2abcos(theta)

=>a^2+b^2+2ab=a^2+b^2+2abcos(theta)

((a+b)^2=a^2+b^2+2ab)

=>2abcos(theta)=2ab

=> cos(theta)=1

=>theta=0 degree

Answer 2

Answer:

The answer is 180 degree

Explanation:

resultant [A] will have its minimum value due to negative sign.

for this cos theta must have minimum value because                                                                {|A|=($B^{2} +C^{2} -2BCcostheta$)^1/2}

Minimum value of cos theta is -1 for which theta=180 degree