Finding Critical Point: x for y=3e^(-2x)−5e^(-4x)

In summary, a critical point is a point on a graph where the derivative is equal to zero or does not exist. To find the critical points of a function, take the derivative, set it equal to zero, and solve for the variable. These points are important in identifying features of the function and for optimization problems. To determine the nature of a critical point, the second derivative test can be used. A function can have multiple critical points, but not all of them may be significant in understanding the function's behavior.
  • #1
Recce
6
0
y = 3e^(−2x) −5e^(−4x)
y'= −6e^(−2x)+20e^(−4x)
How do I find the critical point at x?
The answer is (1/2)ln(10/3) but I don't know how to get that answer

Thank you
 
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  • #2
Okay, you have correctly computed:

\(\displaystyle y'=-6e^{-2x}+20e^{-4x}\)

And critical values are found for $y'=0$, so:

\(\displaystyle -6e^{-2x}+20e^{-4x}=0\)

Multiply through by \(\displaystyle -\frac{e^{4x}}{2}\ne0\):

\(\displaystyle 3e^{2x}-10=0\)

\(\displaystyle e^{2x}=\frac{10}{3}\)

Convert from exponential to logarithmic form:

\(\displaystyle 2x=\ln\left(\frac{10}{3}\right)\)

Hence, dividing through by 2, we obtain:

\(\displaystyle x=\frac{1}{2}\ln\left(\frac{10}{3}\right)\)
 

FAQ: Finding Critical Point: x for y=3e^(-2x)−5e^(-4x)

What is a critical point?

A critical point is a point on a graph where the derivative (slope) is equal to zero or does not exist. It can also be referred to as a stationary point.

How do you find the critical points of a function?

To find the critical points of a function, you must first take the derivative of the function. Then, set the derivative equal to zero and solve for the variable to find the x-values of the critical points.

What is the importance of finding critical points?

Finding critical points helps us to identify important features of a function, such as the maximum and minimum values. It is also useful in optimization problems, where we want to find the maximum or minimum value of a function.

How do you determine if a critical point is a maximum, minimum, or neither?

To determine the nature of a critical point, we can use the second derivative test. If the second derivative is positive at the critical point, it is a minimum. If the second derivative is negative, it is a maximum. And if the second derivative is zero, the test is inconclusive and we must use other methods to determine the nature of the critical point.

Can a function have more than one critical point?

Yes, a function can have multiple critical points. These are points on the graph where the derivative is equal to zero or does not exist. However, not all critical points are necessarily significant or important in understanding the behavior of a function.

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