Ready solution of the problem. The sorcerer of Arutyunov. Task number 263.

261 - 270. Given a function z = f (x; y), the point A (x0; y0) and the vector ā (a1; a2). Find: 1) gradz at the point A; 2) the derivative at the point A in the direction of the vector ā.

263. z = ln (5x2 + 3y2), A (1,1); Ā = 3i + 2j

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Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)