99.8k views
5 votes
Solve irrational equation pls

Solve irrational equation pls-example-1

1 Answer

4 votes

\hbox{Domain:}\\ x^2+x-2\geq0 \wedge x^2-4x+3\geq0 \wedge x^2-1\geq0\\ x^2-x+2x-2\geq0 \wedge x^2-x-3x+3\geq0 \wedge x^2\geq1\\ x(x-1)+2(x-1)\geq 0 \wedge x(x-1)-3(x-1)\geq0 \wedge (x\geq 1 \vee x\leq-1)\\ (x+2)(x-1)\geq0 \wedge (x-3)(x-1)\geq0\wedge x\in(-\infty,-1\rangle\cup\langle1,\infty)\\ x\in(-\infty,-2\rangle\cup\langle1,\infty) \wedge x\in(-\infty,1\rangle \cup\langle3,\infty) \wedge x\in(-\infty,-1\rangle\cup\langle1,\infty)\\ x\in(-\infty,-2\rangle\cup\langle3,\infty)



√(x^2+x-2)+√(x^2-4x+3)=√(x^2-1)\\ x^2-1=x^2+x-2+2√((x^2+x-2)(x^2-4x+3))+x^2-4x+3\\ 2√((x^2+x-2)(x^2-4x+3))=-x^2+3x-2\\ √((x^2+x-2)(x^2-4x+3))=(-x^2+3x-2)/(2)\\ (x^2+x-2)(x^2-4x+3)=\left((-x^2+3x-2)/(2)\right)^2\\ (x+2)(x-1)(x-3)(x-1)=\left((-x^2+x+2x-2)/(2)\right)^2\\ (x+2)(x-3)(x-1)^2=\left((-x(x-1)+2(x-1))/(2)\right)^2\\ (x+2)(x-3)(x-1)^2=\left((-(x-2)(x-1))/(2)\right)^2\\ (x+2)(x-3)(x-1)^2=((x-2)^2(x-1)^2)/(4)\\ 4(x+2)(x-3)(x-1)^2=(x-2)^2(x-1)^2\\

4(x+2)(x-3)(x-1)^2-(x-2)^2(x-1)^2=0\\ (x-1)^2(4(x+2)(x-3)-(x-2)^2)=0\\ (x-1)^2(4(x^2-3x+2x-6)-(x^2-4x+4))=0\\ (x-1)^2(4x^2-4x-24-x^2+4x-4)=0\\ (x-1)^2(3x^2-28)=0\\ x-1=0 \vee 3x^2-28=0\\ x=1 \vee 3x^2=28\\ x=1 \vee x^2=(28)/(3)\\ x=1 \vee x=\sqrt{(28)/(3)} \vee x=-\sqrt{(28)/(3)}\\

There's one more condition I forgot about

-(x-2)(x-1)\geq0\\ x\in\langle1,2\rangle\\

Finally

x\in(-\infty,-2\rangle\cup\langle3,\infty) \wedge x\in\langle1,2\rangle \wedge x=\{1,\sqrt{(28)/(3)}, -\sqrt{(28)/(3)}\}\\ \boxed{\boxed{x=1}}
User Csomakk
by
8.2k points