Vectors a and b have identical magnitudes of 7.5 units. find the angle between them if a + b = 7.5 3 ĵ. (enter the smallest positive angle in degrees.)

For this case you can find the module of the sum of the two vectors by means of the following equation
 a + b = root (a^2 + b^2 + 2*a*b*cos (x)) --- Eq1
 On the other hand the vector a + b is
 a + b = 7.5*3 ĵ = 22.5 j
 The module of a + b is
 a + b = Root (22.5^2) = 22.5
 Substituting values in Eq1
 22.5 = root ((7.5)^2 + (7.5)^2 + 2*(7.5)*(7.5)*cos (x))
 Clearing
 x = arccos [((22.5^2) - (7.5)^2 - (7.5)^2)/(2*(7.5)*(7.5))]
 x = ARCOS (3.5)
 the angle between a and b in degrees is
 x = ARCOS (3.5*(180/pi))
 

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.

Ican’t sorry i would if i could