1. The problem statement, all variables and given/known data In the figure particles 1 and 2 of charge q1 = q2 = +24.00 × 10-19 C are on a y axis at distance d = 18.0 cm from the origin. Particle 3 of charge q3 = +17.60 × 10-19 C is moved gradually along the x axis from x = 0 to x = +6.47 m. At what values of x will the magnitude of the electrostatic force on the third particle from the other two particles be (a) minimum and (b) maximum? What are the (c) minimum and (d) maximum magnitudes? 2. Relevant equations E field strength at position r = kq/r^2 E force = kq1q2/r^2 3. The attempt at a solution I got the minimum, so (a) is complete - it's just 0 cm. I would like to start with (b). I am confused about (b). I imagine that the closer you get to 0 cm, the more powerful the force would be on q3, since the distance would be minimal, but not equal to 0 cm, since 0 cm is the location of the minimum. However, I think this is incorrect. Do I have to find the maximum using a derivative? If so, could you guys help me get started with this? Thanks so much in advance!