JEE Main 2017 · 8 April · Online · Mathematics · Limits
A. 12\dfrac{1}{\sqrt{2}}21
Given,
limx→33x−32x−4−2\lim_{x \to 3} \dfrac{\sqrt{3x} - 3}{\sqrt{2x - 4} - \sqrt{2}}limx→32x−4−23x−3On rationalization we get,limx→3(3x−9)×(2x−4+2){(2x−4)−2}×(3x+3)\lim_{x \to 3} \dfrac{\left(3x - 9\right) \times \left(\sqrt{2x - 4} + \sqrt{2}\right)}{\left\{\left(2x - 4\right) - 2\right\} \times \left(\sqrt{3x} + 3\right)}limx→3{(2x−4)−2}×(3x+3)(3x−9)×(2x−4+2)=limx→33(x−3)2(x−3)×2x−4+2(3x+3)= \lim_{x \to 3} \dfrac{3\left(x - 3\right)}{2\left(x - 3\right)} \times \dfrac{\sqrt{2x - 4} + \sqrt{2}}{\left(\sqrt{3x} + 3\right)}=limx→32(x−3)3(x−3)×(3x+3)2x−4+2=32×226=12.= \dfrac{3}{2} \times \dfrac{2\sqrt{2}}{6} = \dfrac{1}{\sqrt{2}} .=23×622=21.