Calculate the exact value at the point (x, y) = (2, 1) of the following second order partial derivative 2 2 f ayax where f (x , y ) = + Enter the answer as a fraction. a2 f (2, 1 ) = 1 Check (3) standard function logic vector abc unit ENG Search US 20 ASUS VivoBook F7 F8 FO FIC F12 F2 F3 FA F5 F6 Prt Sc Insert Delet Boc 2 5 8