Question
Solve the inequality with square root
\sqrt{x+2}-\sqrt{x-1}>\sqrt{2x-3}
for real values of x
Solve the inequality with square root
\sqrt{x+2}-\sqrt{x-1}>\sqrt{2x-3}
for real values of x
Since \sqrt{2x-3}\geq 0 , squaring both sides of the inequality will not change the direction of the sign of the inequality.
x+2-2\sqrt{x+2}\sqrt{x-1}+x-1>2x-3
Simplifying the squared inequality, we get
\sqrt{x+2}\sqrt{x-1}< 2
Since the LHS of square roots is greater than 0, we can square again without changing the sign of the inequality.
(x+2)(x-1) <4
Rearranging the inequality,
x^2+x-6<0
Solving the the quadratic gives
In the meantime,
since the radicand of a square root is not less than 0,
for \sqrt{x+2} to be real, x+2\geq 0,
for \sqrt{x-1} to be real , x-1\geq 0,
for \sqrt{2x-3} to be real, 2x-3\geq 0
Therefore, the range of (1) is further narrowed to
\dfrac{3}{2}\leq x<2