Write a polynomial equation of degree 3 such that two of its roots are 2 and an imaginary number.
Solution:
A polynomial equation of degree 3 such that two of its roots are 2 and an imaginary number [Given]
We know that the equation has 3 roots one is 2 and the other two are imaginary
If one root is 2 then the equation must have (x - 2) as its factor.
Consider i, -i as the other two imaginary numbers
(x - i)(x + i)
Roots of the polynomial of degree 3 is (x - 2)(x - i)(x + i)
Solve the roots to get the equation
(x - 2)(x2 + xi - xi - i2)
We know that i2 = 1
= (x - 2)(x2 - i2)
So we get
= (x3 + x - 2x2 - 2)
= x3 - 2x2 + x - 2
Therefore, the polynomial equation of degree 3 is (x3 - 2x2 + x - 2).
Write a polynomial equation of degree 3 such that two of its roots are 2 and an imaginary number.
Summary:
The polynomial equation of degree 3 such that two of its roots are 2 and an imaginary number is (x3 - 2x2 + x - 2).
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