Calculate Derivative: To find the critical points of the function f(x)=8x3−24x−36, we need to find the values of x where the first derivative f′(x) is equal to zero or undefined.
Set Derivative Equal: First, we calculate the first derivative of f(x). The derivative of 8x3 is 24x2, the derivative of −24x is −24, and the derivative of a constant −36 is 0. So, f′(x)=24x2−24.
Simplify Equation: Next, we set the first derivative equal to zero to find the critical points: 24x2−24=0.
Factorize Equation: We can simplify the equation by dividing both sides by 24, which gives us x2−1=0.
Find Solutions: The equation x2−1=0 can be factored into (x+1)(x−1)=0.
Check Domain: Setting each factor equal to zero gives us two possible solutions for x: x+1=0 and x−1=0.
Check Domain: Setting each factor equal to zero gives us two possible solutions for x: x+1=0 and x−1=0.Solving x+1=0 gives us x=−1. Solving x−1=0 gives us x=1. These are the x-values where the first derivative is zero.
Check Domain: Setting each factor equal to zero gives us two possible solutions for x: x+1=0 and x−1=0.Solving x+1=0 gives us x=−1. Solving x−1=0 gives us x=1. These are the x-values where the first derivative is zero.We need to check if these points are within the domain of the original function f(x). Since f(x) is a polynomial, its domain is all real numbers, so both x=−1 and x=1 are within the domain.
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