4. Consider functions \(f(x, y)=\sqrt[3]{x^{3}+y^{3}}\) and \(\mathbf{c}(t)=(t, 2 t)\).
(a) Show that \(f_{x}(0,0)\) and \(f_{y}(0,0)\) exist. What is \(\nabla f(0,0)\) ?
(b) Show that \(f\) is not differentiable at the point \((0,0)\).
(c) Find \((f \circ c)(t)\) and then compute its derivative at the point \(t=0\).
(d) Show that \((f \circ \mathbf{c})^{\prime}(0) \neq \nabla f(\mathbf{c}(0)) \cdot \mathbf{c}^{\prime}(0)\). Does this contradict the chain rule formula? why? why not?
Question 1. Compute the derivative of the following functions.(a) \(f(x)=x^{3}-\frac{2}{\sqrt{x}}+4\)(b) \(f(x)=2^{3 x-1}\)(c) \(f(x)=\ln \left(5 x^{2}+1\right)\)(d) \(f(x)=\frac{\tan (x)}{x^{2}+1}\)(e) \(f(x)=e^{x^{2}} \cdot \arctan (2 x)\)(f) \(f(x)=\sin (x)^{2} \cdot\left(\tan (x)+\cos (x)^{2}\right)\).Question 2. In geometry, the folium of Descartes is a curve given by the equation$$ x^{3}+y^{3}-3 a x y=0 $$Here, \(a\) is a constant.The curve was first proposed by Descartes in 1638 . Its claim to fame lies in an incident in the development of calculus. Descartes challenged Fermat to find the tangent line...
Consider the function \(f(x, y)=\frac{x y}{x^{2}+y^{2}}\) if \((x, y) \neq(0,0)\)$$ =0 \text { if }(x, y)=(0,0) $$Which one of the statement is incorrect.Select one:a. \(f(x, y)\) is differentiable everywhere.b. \(f(x, y)\) is differentiable everywhere except at the origin.c. \(f(x, y)\) is not continuousd. First partial derivatives \(f(x, y)\) exist.e. \(\lim _{(x, y) \rightarrow(0,0)} \frac{x y}{x^{2}+y^{2}}\) does not exist.
showing multivariable calculus functions are differentiable
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2. Recall that by Theorem 3 of Section 14.3, a function f(x,y) is differentiable if its partial derivatives fa and fy both exist and are continuous. (a) Use this idea to show that the function f(x,y)-esin ry is differentiable. (b) Let o be a differentiable function and f(,)Jy Find the partial derivatives of f and determine whether they are continuous. Hint: The Fundamental Theorem of Calculus gives us that Ø has an...
Suppose that the functions \(f: \mathbb{R}^{3} \rightarrow \mathbb{R}, g: \mathbb{R}^{3} \rightarrow \mathbb{R}\), and \(h: \mathbb{R}^{3} \rightarrow \mathbb{R}\) are continuously differentiable and let \(\left(x_{0}, y_{0}, z_{0}\right)\) be a point in \(\mathbb{R}^{3}\) at which$$ f\left(x_{0}, y_{0}, z_{0}\right)=g\left(x_{0}, y_{0}, z_{0}\right)=h\left(x_{0}, y_{0}, z_{0}\right)=0 $$and$$ \left\langle\nabla f\left(x_{0}, y_{0}, z_{0}\right), \nabla g\left(x_{0}, y_{0}, z_{0}\right) \times \nabla h\left(x_{0}, y_{0}, z_{0}\right)\right\rangle \neq 0 $$By considering the set of solutions of this system as consisting of the intersection of a surface with a path, explain why that in a...
Complex analysis(i) If \(f\) is differentiable at \(z_{0}\) then \(f\) is continuous at \(z_{0}\).(ii) If \(f\) and \(g\) are differentiable at \(z_{0}\), then \(f+g\) and \(f g\) also are, and \((f+g)^{\prime}\left(z_{0}\right)=f^{\prime}\left(z_{0}\right)+g^{\prime}\left(z_{0}\right) \quad\) (sum rule); \((f g)^{\prime}\left(z_{0}\right)=f^{\prime}\left(z_{0}\right) g\left(z_{0}\right)+f\left(z_{0}\right) g^{\prime}\left(z_{0}\right) \quad\) (product rule). If in addition \(g\left(z_{0}\right) \neq 0\), then \(f / g\) is differentiable at \(z_{0}\), and \(\left(\frac{f}{g}\right)^{\prime}\left(z_{0}\right)=\frac{f^{\prime}\left(z_{0}\right) g\left(z_{0}\right)-f\left(z_{0}\right) g^{\prime}\left(z_{0}\right)}{g\left(z_{0}\right)^{2}} \quad\) (quotient rule).(iii) If \(f\) is differentiable at \(z_{0}\) and \(g\) is differentiable at \(f\left(z_{0}\right)\), then the composite function \(g \circ...
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is somewhat difficult. In practice, it is often easier to show a stronger condition: if each partial derivative OJi = 1, ... , n, is continuous in a disc around p = _ (a1.... , an), then f is differentiable дх, (a1,., an) Put differently: if f is continuously differentiable at p, it is differentiable at However, just as in the one-variable case, there are functions that are differentiable but not at p = p. continuously differentiable....
Exercise 31: (Chain rule) Let g : la,b] → R be differentiable and strictly increasing and f : R-IR be continuous. Show that gr) F(x) :=| f(t)dt Jg(a) is differentiable and compute its derivative
Exercise 31: (Chain rule) Let g : la,b] → R be differentiable and strictly increasing and f : R-IR be continuous. Show that gr) F(x) :=| f(t)dt Jg(a) is differentiable and compute its derivative
4. Consider the functions f : R2 R2 and g R2 R2 given by f(x, y) (x, xy) and g(x, y)-(x2 + y, x + y) (a) Prove that f and g are differentiable everywhere. You may use the theorem you stated in (b) Call F-fog. Properly use the Chain Rule to prove that F is differentiable at the point question (1c). (1,1), and write F'(1, 1) as a Jacobian matrix.
4. Consider the functions f : R2 R2 and...
1. ( 8 points) An object moves though a vector field, \(\overrightarrow{\mathbf{F}}(x, y)\), along a circular path, \(\overrightarrow{\mathbf{r}}(t)\), starting at \(P\) and ending at \(Q\) as shown in the graph below.(a) At the point \(R\) draw and label a tangent vector in the direction of \(d \overrightarrow{\mathbf{r}}\).(b) At the point \(R\) draw and label a vector in the direction of the vector filed, \(\overrightarrow{\mathbf{F}}(R)\).(c) At the point \(R\) is \(\overrightarrow{\mathbf{F}} \cdot d \overrightarrow{\mathbf{r}}\) positive, negative, or zero? Circle the correct...
Exercise 1. Do the following: (a) Write a statement defining the Chain Rule for the functions g: R" → Rm and f: RM + RP. Then describe how it works in a paragraph, assuming the reader is a classmate who has been following the course but missed the lecture on Properties of the Derivative. (b) Explain in detail how the Chain Rule you learned in Calculus I, (fog)(x) = f (g(2)).g'(x), is really just the special case of your statement...