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lim_(x rarr3)(sqrt(2x-5)-1)/(x-3)=

limx32x51x3= \lim _{x \rightarrow 3} \frac{\sqrt{2 x-5}-1}{x-3}=

Full solution

Q. limx32x51x3= \lim _{x \rightarrow 3} \frac{\sqrt{2 x-5}-1}{x-3}=
  1. Identify Function & Point: Identify the function and the point at which we need to find the limit. We have the function f(x)=2x51x3f(x) = \frac{\sqrt{2x-5}-1}{x-3} and we need to find the limit as xx approaches 33.
  2. Direct Substitution Check: Direct substitution to check if the limit can be found this way.\newlineLet's substitute x=3x = 3 into the function to see if we get a determinate form.\newlinef(3)=(2351)/(33)=(651)/(0)=(11)/0=(11)/0=0/0f(3) = (\sqrt{2\cdot 3-5}-1)/(3-3) = (\sqrt{6-5}-1)/(0) = (\sqrt{1}-1)/0 = (1-1)/0 = 0/0\newlineWe get an indeterminate form 0/00/0, so we cannot use direct substitution to find the limit.
  3. Algebraic Manipulation: Apply algebraic manipulation to simplify the expression.\newlineTo resolve the indeterminate form, we can multiply the numerator and the denominator by the conjugate of the numerator.\newlineThe conjugate of 2x51\sqrt{2x-5}-1 is 2x5+1\sqrt{2x-5}+1.\newlineLet's multiply the numerator and denominator by this conjugate.\newlinef(x)=2x51x32x5+12x5+1f(x) = \frac{\sqrt{2x-5}-1}{x-3} \cdot \frac{\sqrt{2x-5}+1}{\sqrt{2x-5}+1}
  4. Multiplication & Simplification: Perform the multiplication in the numerator and simplify.\newlineWhen we multiply the numerators, we get:\newline2x51\sqrt{2x-5}-12x5+1\sqrt{2x-5}+1 = (2x5)(1)2=2x51=2x6(2x-5) - (1)^2 = 2x - 5 - 1 = 2x - 6\newlineThe denominator becomes (x3)(2x5+1)(x-3)(\sqrt{2x-5}+1).\newlineSo now we have:\newlinef(x)=2x6(x3)(2x5+1)f(x) = \frac{2x - 6}{(x-3)(\sqrt{2x-5}+1)}
  5. Factor Out & Simplify: Factor out common terms and simplify the expression further.\newlineNotice that 2x62x - 6 can be factored as 2(x3)2(x - 3).\newlinef(x)=2(x3)(x3)(2x5+1)f(x) = \frac{2(x - 3)}{(x-3)(\sqrt{2x-5}+1)}\newlineNow we can cancel out the (x3)(x - 3) term in the numerator and denominator.\newlinef(x)=2(2x5+1)f(x) = \frac{2}{(\sqrt{2x-5}+1)}
  6. Direct Substitution: Now that the expression is simplified, we can try direct substitution again. Let's substitute x=3x = 3 into the simplified function. f(3)=2(235+1)=2(65+1)=2(1+1)=2(1+1)=22=1f(3) = \frac{2}{(\sqrt{2\cdot 3-5}+1)} = \frac{2}{(\sqrt{6-5}+1)} = \frac{2}{(\sqrt{1}+1)} = \frac{2}{(1+1)} = \frac{2}{2} = 1

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