Find Polynomial Equation: 3 Zeros, f(2)=91

  • Thread starter red_raider
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In summary, you need to find a polynomial equation with the givens n=3, -5 and 4+3i as zeros, and f(2)=91. The hint is to use the fact that if 4+3i is a zero, then 4-3i is also a zero. The polynomial should be of the form c*(x+5)(x-4-3i)(x-4+3i), where c is some constant. However, it is important to note that if the coefficients are complex numbers, the given information is not enough to determine the polynomial.
  • #1
red_raider
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I need to find the polynomial equation. The givens are: n=3; -5 and 4+3i are zeros; f(2)=91
I have no idea how to find this? Can you please help
 
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  • #2
is n the degree of the polynomial?

Hint: if 4+3i is a zero, then 4-3i is a zero.

So you know that your polynomial is of the form c*(x+5)(x-4-3i)(x-4+3i), where c is some constant.

Now you need to figure out what c is.
 
  • #3
grief is also assuming that all coefficients are real numbers. It is also possible to have a polynomial with complex coefficients but then the information given would not be enough to determine the polynomial.
 
  • #4
"grief is also assuming that all coefficients are real numbers. It is also possible to have a polynomial with complex coefficients but then the information given would not be enough to determine the polynomial."

I must be misunderstanding: both by hand and with Scilab I obtain specific real and complex parts for a polynomial that has the o.p.'s specifications (zeros and value for x = 0). It would seem that the "initial condition" nails down the leading coefficient, and the factors that correspond to the zeros do the rest.

I've been grading all afternoon, so am rather zonked. What simple thing am I missing?
 

What does it mean to find a polynomial equation with 3 zeros and a given function value?

Finding a polynomial equation with 3 zeros and a given function value means finding a polynomial function that has 3 distinct values where the output is equal to zero, and one specific input value where the output is equal to the given function value.

How do I find a polynomial equation with 3 zeros and a given function value?

To find a polynomial equation with 3 zeros and a given function value, you can use the fact that a polynomial function with 3 zeros can be written in the form f(x) = a(x-x1)(x-x2)(x-x3), where a is a constant and x1, x2, and x3 are the zeros. You can then use the given function value to find the value of a, and you will have your polynomial equation.

What do I do if I have more than 3 zeros or more than one given function value?

If you have more than 3 zeros or more than one given function value, you can still use the same method as mentioned above. You will just have to use a higher degree polynomial, such as f(x) = a(x-x1)(x-x2)(x-x3)(x-x4)... or use a system of equations to solve for the coefficients.

Can I use any number for the zeros and the given function value?

Yes, you can use any real number for the zeros and the given function value. However, keep in mind that the more complex the numbers are, the more complicated the resulting polynomial equation will be.

Why is it important to find a polynomial equation with specific zeros and a given function value?

Finding a polynomial equation with specific zeros and a given function value can be useful in solving real-world problems and modeling data. It allows us to create a function that accurately represents the given information and can be used to make predictions or solve equations.

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