find roots of x^3 - 2x^2 +1 if one root is 1?
Answers (2)
12th Jul, 2020
Hello,
Divide the whole equation by (x-1) as 1 is the root of the equation. Then you'll get a quadratic equation.
Factorise the quadratic equation, which gives you 2 remaining roots.
Divide the whole equation by (x-1) as 1 is the root of the equation. Then you'll get a quadratic equation.
Factorise the quadratic equation, which gives you 2 remaining roots.
Comments (0)
12th Jul, 2020
Let other roots be a and b.
Now, a+b+1 = 2 which gives a+b = 1
and a.b.1 = -1 which gives ab = -1
putting a = 1 - b from the first equation in the second, we get
(1-b)b = -1
Solving the above equation, we get b = (1+\root(5))/2 and b = (1-\root(5))/2
hence, the other two roots are (1+\root(5))/2 and (1-\root(5))/2.
Hope this helps.
Comments (0)
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