Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Let 
g(x)=xe^(3x).
What is the absolute minimum value of 
g ?
Choose 1 answer:
(A) 
-(1)/(3e)
(B) 
(3)/(e^(3))
(C) 
-(1)/(e^(3))
(D) 
g has no minimum value

Let g(x)=xe3x g(x)=x e^{3 x} .\newlineWhat is the absolute minimum value of g g ?\newlineChoose 11 answer:\newline(A) 13e -\frac{1}{3 e} \newline(B) 3e3 \frac{3}{e^{3}} \newline(C) 1e3 -\frac{1}{e^{3}} \newline(D) g g has no minimum value

Full solution

Q. Let g(x)=xe3x g(x)=x e^{3 x} .\newlineWhat is the absolute minimum value of g g ?\newlineChoose 11 answer:\newline(A) 13e -\frac{1}{3 e} \newline(B) 3e3 \frac{3}{e^{3}} \newline(C) 1e3 -\frac{1}{e^{3}} \newline(D) g g has no minimum value
  1. Find Derivative: To find the absolute minimum value of the function g(x)=xe3xg(x) = xe^{3x}, we need to find the critical points by taking the derivative of g(x)g(x) and setting it equal to zero.\newlineLet's find the derivative g(x)g'(x).\newlineg(x)=ddx[xe3x]g'(x) = \frac{d}{dx} [xe^{3x}]\newlineUsing the product rule, where (uv)=uv+uv(u*v)' = u'v + uv', let u=xu = x and v=e3xv = e^{3x}.\newlineu=ddx[x]=1u' = \frac{d}{dx} [x] = 1\newlinev=ddx[e3x]=3e3xv' = \frac{d}{dx} [e^{3x}] = 3e^{3x}\newlineNow apply the product rule.\newlineg(x)=uv+uvg'(x) = u'v + uv'\newlineg(x)g(x)00\newlineg(x)g(x)11
  2. Set Equal to Zero: Now we set the derivative equal to zero to find the critical points.\newline0=e3x+3xe3x0 = e^{3x} + 3xe^{3x}\newlineFactor out e3xe^{3x} from both terms.\newline0=e3x(1+3x)0 = e^{3x}(1 + 3x)\newlineSince e3xe^{3x} is never zero, we can divide both sides by e3xe^{3x} to get:\newline0=1+3x0 = 1 + 3x\newlineNow solve for x.\newline1=3x-1 = 3x\newlinex = 13-\frac{1}{3}
  3. Critical Point Analysis: We have found a critical point at x=13x = -\frac{1}{3}. To determine if this is a minimum, we can use the second derivative test or analyze the behavior of the first derivative around the critical point. Let's use the second derivative test.\newlineFind the second derivative g(x)g''(x).\newlineg(x)=ddx[g(x)]g''(x) = \frac{d}{dx} [g'(x)]\newline=ddx[e3x+3xe3x]= \frac{d}{dx} [e^{3x} + 3xe^{3x}]\newlineUsing the product rule again for the second term, where u=3xu = 3x and v=e3xv = e^{3x}, we get:\newlineu=ddx[3x]=3u' = \frac{d}{dx} [3x] = 3\newlinev=ddx[e3x]=3e3xv' = \frac{d}{dx} [e^{3x}] = 3e^{3x}\newlineNow apply the product rule.\newlineg(x)=ddx[e3x]+ddx[3xe3x]g''(x) = \frac{d}{dx} [e^{3x}] + \frac{d}{dx} [3xe^{3x}]\newline=3e3x+3e3x+3x3e3x= 3e^{3x} + 3e^{3x} + 3x \cdot 3e^{3x}\newlineg(x)g''(x)00\newlineg(x)g''(x)11
  4. Second Derivative Test: Now we evaluate the second derivative at the critical point x=13x = -\frac{1}{3}.g(13)=6e1+9(13)e1=6e3e=63e=3eg''\left(-\frac{1}{3}\right) = 6e^{-1} + 9\left(-\frac{1}{3}\right)e^{-1} = \frac{6}{e} - \frac{3}{e} = \frac{6 - 3}{e} = \frac{3}{e}Since 3e\frac{3}{e} is positive, the second derivative is positive at x=13x = -\frac{1}{3}, which means the function is concave up at this point, and thus x=13x = -\frac{1}{3} is a local minimum. Because the function g(x)=xe3xg(x) = xe^{3x} goes to negative infinity as xx goes to negative infinity and to positive infinity as xx goes to positive infinity, this local minimum is also the absolute minimum.
  5. Evaluate Second Derivative: Now we need to find the value of g(x)g(x) at the critical point x=13x = -\frac{1}{3} to determine the absolute minimum value.g(13)=(13)e3(13)g\left(-\frac{1}{3}\right) = \left(-\frac{1}{3}\right)e^{3\left(-\frac{1}{3}\right)} =(13)e1= \left(-\frac{1}{3}\right)e^{-1} =(13e)= -\left(\frac{1}{3e}\right) This corresponds to answer choice (A).

More problems from Multiplication with rational exponents