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Tangent planes Find the equation of the plane tangent to the surface z = 2ya + 2 ya at the point (-1, -2). The equation of the plane is z = y+Second partial derivatives Find all the second partial derivatives of the function f(x, y) = x cos(2y x) NOTE: Remember that the two mixed partial derivatives must be equal. fry = _ fyr = fyy =Partial derivatives Find the first partial derivatives of the function aw) = 3mg + 3y4