Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Find all critical points of 
f(x)=8x^(3)-24 x-36.

Find all critical points of f(x)=8x324x36 f(x)=8 x^{3}-24 x-36 .

Full solution

Q. Find all critical points of f(x)=8x324x36 f(x)=8 x^{3}-24 x-36 .
  1. Calculate Derivative: To find the critical points of the function f(x)=8x324x36f(x) = 8x^3 - 24x - 36, we need to find the values of xx where the first derivative f(x)f'(x) is equal to zero or undefined.
  2. Set Derivative Equal: First, we calculate the first derivative of f(x)f(x). The derivative of 8x38x^3 is 24x224x^2, the derivative of 24x-24x is 24-24, and the derivative of a constant 36-36 is 00. So, f(x)=24x224f'(x) = 24x^2 - 24.
  3. Simplify Equation: Next, we set the first derivative equal to zero to find the critical points: 24x224=024x^2 - 24 = 0.
  4. Factorize Equation: We can simplify the equation by dividing both sides by 2424, which gives us x21=0x^2 - 1 = 0.
  5. Find Solutions: The equation x21=0x^2 - 1 = 0 can be factored into (x+1)(x1)=0(x + 1)(x - 1) = 0.
  6. Check Domain: Setting each factor equal to zero gives us two possible solutions for xx: x+1=0x + 1 = 0 and x1=0x - 1 = 0.
  7. Check Domain: Setting each factor equal to zero gives us two possible solutions for xx: x+1=0x + 1 = 0 and x1=0x - 1 = 0.Solving x+1=0x + 1 = 0 gives us x=1x = -1. Solving x1=0x - 1 = 0 gives us x=1x = 1. These are the xx-values where the first derivative is zero.
  8. Check Domain: Setting each factor equal to zero gives us two possible solutions for xx: x+1=0x + 1 = 0 and x1=0x - 1 = 0.Solving x+1=0x + 1 = 0 gives us x=1x = -1. Solving x1=0x - 1 = 0 gives us x=1x = 1. These are the xx-values where the first derivative is zero.We need to check if these points are within the domain of the original function f(x)f(x). Since f(x)f(x) is a polynomial, its domain is all real numbers, so both x=1x = -1 and x=1x = 1 are within the domain.

More problems from Solve complex trigonomentric equations