The problem is asking us to isolate B. The given equation is solved for P, and we need to rearrange it for B.
First we need to square both sides. This will cancel out the square root on the right side.
P^2 = E + A^2/B^2
Next, subtract E from both sides.
P^2 - E = A^2/B^2
Next we need to get the B^2 out of the denominator. Multiply both sides by B^2.
B^2(P^2 - E) = A^2
Next divide both sides by (P^2 - E).
B^2 = A^2/(P^2 - E)
Lastly, take the square root of both sides.
B = sqrt(A^2/(P^2 - E))
