Step 1: Find the first derivative of the curve to find the stationary point.

            Skill 1; Apply the deviation on both both sides

                         \frac{dy}{dx} = \frac{dy}{dx} (x^4 - 8x^2 + 3)

            Skill 2: Differentiate the given equation

                           \frac{dy}{dx} = 4x^3 - 16x

Step 2: Take \frac{dy}{dx} = 0 and  Solve the equation of unknown values.

                             4x^3 - 16x = 0

                            [math] 4x[(x^2) - 4] = 0[/math]

                                   x^2 = 4

                                  x=\pm2

Step 3: Substitute this coordinate in the given curve to find the another coordinate of the stationary point.