Given the y-intercept of this curve means what? Diff EQ

In summary: Thanks for the heads up, and the reassurance that I'm not alone in this!In summary, the y-intercept of the curve y = f(x) is 2. This means that y(0)= 2.
  • #1
mr_coffee
1,629
1
Hello everyone this may be an easy problem, but I'm confused on what they have given me the problem says:

Find f(x) if y = f(x) satisfies
{dy}/{dx} = 32 yx^{15}
and the y-intercept of the curve y = f(x) is 2.
f(x) = ?


But what does that mean that the y intercept is 2? is that an intial condition? if so what is the value of x? if y = 2? or does that mean y(0) = 2? or does it mean y(2) = 0?

Here is my work:
http://img72.imageshack.us/img72/9646/lastscan8sf.jpg


Any help would be great! thanks! :)
 
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  • #2
You are doing differential equations and you have to ask what "y- intercept" means? Oh, be embarassed!:smile:

The "y-intercept" of a graph may mean either the point at which the graph crosses the y-axis or the y value of that point, since, of course, the x-value of any point on the y-axis is 0. Saying "the y-intercept of the curve y = f(x) is 2" is saying that y(0)= 2.

By the way, is there any reason for dividing by 32? It looks to me like the solution would be simpler if you left it on the right side.
(It especially prevents one from mistakenly writing that [tex]e^{\frac{ln y}{32}}= \frac{y}{32}[/tex]!)
Oh, and ea+b is NOT ea+ eb!
 
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  • #3
Thanks for the advice Ivey, But i seemed to still suck it up in a big way. Here is my new work, still somthing isn't working out! :bugeye:


http://img81.imageshack.us/img81/9937/lastscan5rv.jpg



PS: I am ashamed of myself :biggrin:
 
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  • #4
Check the math on the x side of the equation when you integrate.
 
  • #5
With good reason! Now I feel I have to point out that 32/16 is NOT 9/4!
 
  • #6
Oh f word, I don't nkow how i didn't notice that. I should have been on that like a hobo on a hamsandwitch.
Perhaps its the large intake of coffee products or pure ignorance hah. thanks guys, it works!
PS: I even showed my professor and he didn't catch the whole 32/16 != 9/4, but then again he probably figured I could do basic math.
 

1. What is the y-intercept of a curve in differential equations?

The y-intercept of a curve in differential equations is the value of the dependent variable (y) when the independent variable (x) is equal to zero. It is the point where the curve intersects the y-axis on a graph.

2. How is the y-intercept related to the initial conditions in a differential equation?

The y-intercept is one of the initial conditions in a differential equation. It represents the starting point of the curve and is used, along with other initial conditions, to solve for the general solution of the equation.

3. Can the y-intercept be negative in a differential equation?

Yes, the y-intercept can be negative in a differential equation. It all depends on the specific equation and the values of the initial conditions. In some cases, the y-intercept may represent a negative value, while in others it may be positive.

4. How does changing the y-intercept affect the curve in a differential equation?

Changing the y-intercept in a differential equation will shift the entire curve up or down. This is because the y-intercept represents the starting point of the curve. A positive change in the y-intercept will shift the curve up, while a negative change will shift it down.

5. Can the y-intercept change over time in a differential equation?

No, the y-intercept cannot change over time in a differential equation. It is a fixed value that represents the initial condition of the curve. However, as the independent variable (x) changes, the y-intercept may appear to change due to the shift of the curve.

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