Find the section equation of the square of surface y * 2 = x * 2 + Z at point (3,5,4)

Find the section equation of the square of surface y * 2 = x * 2 + Z at point (3,5,4)

This paper provides a solution: z = x2-z2 and the tangent plane passes through (3,5,4) z'x = 2x = 6, on the plane of y = 5 (z-x), the derivative is 6, then we can get a tangent, the direction vector can be (1,0,6), and through the tangent point (3,5,4) z'y = 2Y = 10, on the plane of x = 5 (Z-Y), the derivative is 10, then we can get another tangent