精華區beta NTU-Exam 關於我們 聯絡資訊
課程名稱︰微積分乙 課程性質︰共同必修 課程教師︰陳其誠 開課學院:管院 開課系所︰管院各系 考試日期(年月日)︰2007/05/01 考試時限(分鐘):110分鐘 是否需發放獎勵金:是 試題 : Write down your answers on the answer sheet. You should include all the necessary calculations and reasoning. (1)For the following functions find the partial derivative fx (a)f(x,y)=e^-(x^2+y^2) (b)f(x,y,z)=sin(y+z) (c)f(x,y,z)=2x√y - 1/(x^2)y (2)Find fxy,if f(x,y)=xy/(x^2 + y^2) (3)Find the following limits: (a) lim sinπ(x+y)/6 / cosπ(-x+y)/6 (x,y)→(1,2) (b) lim xy/(x^2 + y^2) (x,y)→(0,0) (c) lim xy^2/(x^2 + y^2) (x,y)→(0,0) (4)Suppose f(x,y) is a polynomial in x,y and the gradient ▽f(3,4)=(5,12). If v=(3/5,4/5),then the directional derivative Dvf(3,4)=? Find the unit vector u=(u1,u2) such that the directional derivative Duf(3,4)=13. (5)Suppose f(x,y)=√(9x^2 + 4y^2) and z = A + B(x-1) + C(y-2) is the equation of the tangent plan to the surface z=f(x,y) at the point(1,2,5). Find the values of A,B,C. (6)Two chemicals X and Y can cause some change of temperature in an organic system. It is known that the temperature will increase F(x,y) centigrade (。C),if a total amount of x gram of X together with y gram of Y is injected into the system. And F is a differentiable function of x,y. It is also known that if one, with a constant speed 1g/sec, inject X (resp. Y) into the system then the temperature will increase with the speed 5(。C/sec) (resp. 1(。C/sec)). In what speed will the temperature increase, if we injest both with the constant speed 3g/sec for X and 4g/sec for Y? Why? (7)Find the equation of the tangent line to the curve x^2007 + 501xy - 2y^8 + 9=500 at the point (1,2) -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 61.231.11.143
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