Monday, December 24, 2012

Determine all real values of x in the equation (x-1)^(1/2)+(2-x)^(1/2) =1 ?

We'll impose the constraints of existence of square
roots:


x - 1>=0


x
>= 1


2 -x >=0


x
=<2


The interval of admissible values for x is [1 ;
2].


Now, we'll solve the equation. We'll subtract sqrt(2-x)
both sides:


sqrt(x-1) = 1 -
sqrt(2-x)


We'll raise to square both
sides:


x - 1 = 1 - 2sqrt(2-x)+ 2 -
x


We'll combine like terms:


x
- 1 = 3  -x - 2sqrt(2-x)


We'll subtract 3 - x both
sides:


2x - 4 =
-2sqrt(2-x)


We'll divide by
-2:


2 - x = sqrt(2-x)


We'll
raise to square both sides:


4 - 4x + x^2 = 2 -
x


We'll subtract 2 - x:


x^2 -
3x + 2 = 0


(x-1)(x-2) =
0


x-1=0


x =
1


x-2=0


x
= 2


Since both values belong to the interval
of admissible values, we'll accept them as solutions of the
equation.

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