Inverse Variation: Solve for y when x=5

So what is the value of k?In summary, the conversation was about finding the value of y when x = 5 in an equation where y varies inversely as the square of x and y = 1/8 when x = 1. After some attempts, it was determined that the correct equation is y = k/x2 and the value of k is 1/8. Plugging in x = 5, the value of y is 1/200.
  • #1
amanda_
9
0

Homework Statement



If y varies inversely as the square of x, and y = 1/8 when x = 1, find y when x = 5.

y = 8/25
y = 1/200

The Attempt at a Solution


The equation to find this is y=k/x, I know that. I've tried to plug in both given answers to see which ones matched but neither of them did. I'm not sure what to plug in for k or x. I just need someone to correctly set this up for me and I'll be able to solve it.
 
Physics news on Phys.org
  • #2
amanda_ said:

Homework Statement



If y varies inversely as the square of x, and y = 1/8 when x = 1, find y when x = 5.

y = 8/25
y = 1/200


The Attempt at a Solution


The equation to find this is y=k/x, I know that.
No, it says that y varies inversely as the square of x.
amanda_ said:
I've tried to plug in both given answers to see which ones matched but neither of them did. I'm not sure what to plug in for k or x. I just need someone to correctly set this up for me and I'll be able to solve it.
 
  • #3
amanda_ said:
If y varies inversely as the square of x


The Attempt at a Solution


The equation to find this is y=k/x[/QUOTE]

You'll need to try again, if the cube of x is x3, the square of x is?
 
  • #4
rock.freak667 said:
You'll need to try again, if the cube of x is x3, the square of x is?

x2

So if I square 5 and cross multiply it's 8/25. Is that right?
 
Last edited:
  • #5
amanda_ said:
x2

So if I square 5 and cross multiply it's 8/25. Is that right?

No, it's not. You skipped some steps. First, what is the equation? And you know that when x = 1, y = 1/8.
 

FAQ: Inverse Variation: Solve for y when x=5

What does inverse variation mean?

Inverse variation is a mathematical relationship between two variables where one variable increases as the other decreases, and vice versa. This means that as one variable (x) increases, the other variable (y) decreases, and as one variable (x) decreases, the other variable (y) increases.

How do you solve for y in inverse variation?

To solve for y in inverse variation, we can use the formula y = k/x, where k is a constant. In this formula, k represents the proportionality constant, which remains the same for all values of x and y in the inverse variation relationship.

What is the value of k in inverse variation?

The value of k in inverse variation depends on the specific problem or situation. It can be found by substituting the given values of x and y into the formula y = k/x. Once the value of k is determined, it can be used to find the value of y for any given x.

Can inverse variation ever have a value of 0?

Yes, inverse variation can have a value of 0. This occurs when the variable x is 0, which makes the whole equation y = k/0 undefined. In this case, the graph of the inverse variation relationship would have a vertical asymptote at x = 0.

How can inverse variation be represented graphically?

Inverse variation can be represented graphically by a hyperbola, which is a curved line that approaches but never touches the x and y axes. The closer the graph gets to the axes, the larger the value of x and y becomes, representing the inverse relationship between the two variables.

Similar threads

State the domain and range for a given function
Replies
7
Views
1K
Show that the ratio ##x+y:x-y## is increased by subtracting ##y##
Replies
4
Views
970
To find the range of a given ##\sin## function
Replies
15
Views
1K
Express ##x^3+y^3## in terms of ##m## and ##n##
Replies
17
Views
1K
Prove an equation involving inverse circular functions
Replies
6
Views
1K
Finding the inverse of ##y=2^{x}##
Replies
19
Views
3K
Solve the simultaneous equations involving x, y, and their squares
Replies
2
Views
833
Solving a System of Equations via the Matrix Method
Replies
9
Views
2K
Finding the domain (and range) of a logarithmic function
Replies
11
Views
2K
Possible values an expression can take : ##\dfrac{x^2-x-6}{x-3}##
Replies
7
Views
1K

Hot Threads

Recent Insights

Back
Top