Find the value of a and the coordinates Q and T

  • Thread starter Thread starter Saracen Rue
  • Start date Start date
  • Tags Tags
    Coordinates Value
Saracen Rue
Messages
150
Reaction score
10

Homework Statement


The function ##f(x)=2a^2x\left(x-a\right)^2## intersects with the line ##y=ax## at the origin, point ##Q(b,f(b))## and point ##T(c,f(c))## where ##c>b>0##. A probability density function, ##p(x)=ax-f(x)## can be formed over the domain ##[b,c]##.

(a) Determine the exact values for:
  1. The constant, ##a##
  2. The coordinates ##Q## and ##T##
(b) Calculate ##Pr(2^{1/3}≤X≤2^{2/3})## correct to 4 decimal places

Homework Equations


For PDFs: ##∫_b^cf(x)dx=1##

The Attempt at a Solution


I know that for ##p(x)## to be a probability function, the integration of ##p(x)## over the domain ##[b,c]## must equal 1. However, the problem here is that we don't have the values of ##b## or ##c##. Given that part 1 of the question is to find ##a##, I assume we have to find that to be able to find ##b## and ##c##. However, I'm kind of at a loss as how I would go about doing this.
 
Physics news on Phys.org
Saracen Rue said:
we don't have the values of b or c
You know they are such that Q and T lie on the intersection of the two curves, so b and c must be solutions to a certain equation.
 
I'll give you a small hint to get you started: the first step is to solve a couple things simultaneously. You shouldn't have too much trouble with the rest from there :)
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top