In the rectangular coordinate system, a (4, - 3) is the right angle vertex of OAB, and / AB / = 2 / OA /, the coordinates of vector AB are obtained //Represents absolute value, OAB is triangle

In the rectangular coordinate system, a (4, - 3) is the right angle vertex of OAB, and / AB / = 2 / OA /, the coordinates of vector AB are obtained //Represents absolute value, OAB is triangle

Let B (a, b) vector OA = (4-0, - 3-0) = (4, - 3) vector AB = (a, b) - (4, - 3) = (A-4, B + 3) because OA is perpendicular to AB, the product of OA and ab is 0, so (4, - 3). (A-4, B + 3) = 0, that is: 4 (A-4) - 3 (B + 3) = 0 (1) because / AB / = 2 / 0A /, / 0A / = 5, so / AB / = 10, so: (A-4) ^ 2 + (B + 3