The domain of sqrt(x^2-3x+2) is formed from the xalues of x for the expression sqrt(x^2-3x+2) is defined.
To find the domain of sqrt(x^2-3x+2), we must impose the constraint (x^2-3x+2)>0.
To solve the inequality, we'll factorize the quadratic expression:
x^2-3x+2 = x^2 - x - 2x + 2 = 0
We'll factorize the first 2 terms and the next 2 terms, so that:
x(x-1) - 2(x-1) = 0
We'll factorize again and we'll obtain:
(x-1)(x-2)=0
We'll set each factor eqaul to 0.
x-1=0
x=1
x-2=0
x=2
After finding the zeros, we have to test the signs over the 3 intervals:
(-inf,1), (1,2), (2, inf).
We'll choose values from each interval and thest the sign:
For x=0, in interval (-inf,1).
sqrt(0^2-3*0+2) = sqrt2>0
For x=1.5, in interval (1,2)
sqrt(1.5^2-3*1.5+2)=sqrt(2.25 - 4.5 + 2)=sqrt(-0.25) undefined
For x=3, in interval (2, inf)
sqrt(3^2-3*3+2)= sqrt2>0
After testing, we can establish the domain:
Because of the fact that the expression is defined for values of x in the intervals (-inf,1) or (2, inf) and undefined for values of x in the interval (1,2), the domain will be:
Domain: (-inf,1] U [2, inf)
Note: The symbol "U" means reunion of intervals.
We've included also the values x=1 and x=2, because they are the zeros of the expression sqrt(3^2-3*3+2).
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