there are two displacement vectors one of magnitude 3m and other of magnitude 4m,how should the two

We can find the required angle, arrange the vectors accrodingly and then add.

cos θ = (R² - F₁² - F₂²)/(2F₁F₂)

(a) cos θ = (7² - 3² - 4²)/(2x3x4) = 1, hence the angle between them should be 0.

(b)  cos θ = (1² - 3² - 4²)/(2x3x4) = -1, hence the angle between them should be 180 degree.

(c)  cos θ = (5² - 3² - 4²)/(2x3x4) = 0, hence the anlge between them should be 90 degree.

Regards,

Team,

TopperLearning.