Identify Function & Point: Identify the function and the point at which we need to find the limit. We have the function f(x)=x−32x−5−1 and we need to find the limit as x approaches 3.
Direct Substitution Check: Direct substitution to check if the limit can be found this way.Let's substitute x=3 into the function to see if we get a determinate form.f(3)=(2⋅3−5−1)/(3−3)=(6−5−1)/(0)=(1−1)/0=(1−1)/0=0/0We get an indeterminate form 0/0, so we cannot use direct substitution to find the limit.
Algebraic Manipulation: Apply algebraic manipulation to simplify the expression.To resolve the indeterminate form, we can multiply the numerator and the denominator by the conjugate of the numerator.The conjugate of 2x−5−1 is 2x−5+1.Let's multiply the numerator and denominator by this conjugate.f(x)=x−32x−5−1⋅2x−5+12x−5+1
Multiplication & Simplification: Perform the multiplication in the numerator and simplify.When we multiply the numerators, we get:2x−5−12x−5+1 = (2x−5)−(1)2=2x−5−1=2x−6The denominator becomes (x−3)(2x−5+1).So now we have:f(x)=(x−3)(2x−5+1)2x−6
Factor Out & Simplify: Factor out common terms and simplify the expression further.Notice that 2x−6 can be factored as 2(x−3).f(x)=(x−3)(2x−5+1)2(x−3)Now we can cancel out the (x−3) term in the numerator and denominator.f(x)=(2x−5+1)2
Direct Substitution: Now that the expression is simplified, we can try direct substitution again. Let's substitute x=3 into the simplified function. f(3)=(2⋅3−5+1)2=(6−5+1)2=(1+1)2=(1+1)2=22=1
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