Power Functions

[Dinky_Bell]

Find a power function through the two points;

(1,5); (3,27)


*I have absolutly no idea how to do this...if someone can help me i would be greatful...thanx

 

[stapel]

What formula does your book give you as representing a generic "power function"?

Take that formula, and plug the two given (x, y) points into it. This should give you two equations in two variables (probably something like "a" and "b"). Solve the system to find your specific function.

Eliz.

 

[tkhunny]

MS Excel seems to think a "Power Function" is f(x) = a*x^b. Going with that:

f(1) = a*1^b = 5 ==> a = 5

f(3) = 5*3^b = 27

 

[Dinky_Bell]

The formula is v=kd^p

 

[tkhunny]

OK d = x and v = f(x) and there we have it,

 

[stapel]

The formula is v=kd^p

Then your points are (input, output) = (p, v).

So plug your points into the formula. This will give you two equations in k and d. Solve (as shown previously) for the equation.

Eliz.