Math Problem Statement

given f(x)= x^2 +5, find f(3+h)-f(3)/h

Solution

We need to find the expression for f(3+h)f(3)h\frac{f(3+h) - f(3)}{h} given the function f(x)=x2+5f(x) = x^2 + 5.

Step 1: Calculate f(3+h)f(3+h)

Substitute x=3+hx = 3+h into the function f(x)=x2+5f(x) = x^2 + 5: f(3+h)=(3+h)2+5f(3+h) = (3+h)^2 + 5 Expand (3+h)2(3+h)^2: (3+h)2=9+6h+h2(3+h)^2 = 9 + 6h + h^2 So, f(3+h)=9+6h+h2+5=h2+6h+14f(3+h) = 9 + 6h + h^2 + 5 = h^2 + 6h + 14

Step 2: Calculate f(3)f(3)

Substitute x=3x = 3 into f(x)=x2+5f(x) = x^2 + 5: f(3)=32+5=9+5=14f(3) = 3^2 + 5 = 9 + 5 = 14

Step 3: Compute f(3+h)f(3)h\frac{f(3+h) - f(3)}{h}

Now subtract f(3)f(3) from f(3+h)f(3+h): f(3+h)f(3)=(h2+6h+14)14=h2+6hf(3+h) - f(3) = (h^2 + 6h + 14) - 14 = h^2 + 6h Now, divide by hh: f(3+h)f(3)h=h2+6hh\frac{f(3+h) - f(3)}{h} = \frac{h^2 + 6h}{h} Simplify the expression: f(3+h)f(3)h=h+6\frac{f(3+h) - f(3)}{h} = h + 6

Final Answer:

h+6\boxed{h + 6}

Would you like to explore this further or have any questions?

Here are some related questions you might find interesting:

  1. How would you find the derivative of f(x)=x2+5f(x) = x^2 + 5 using the limit definition?
  2. What happens to the expression f(3+h)f(3)h\frac{f(3+h) - f(3)}{h} as hh approaches 0?
  3. How do you calculate f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} for a general function f(x)f(x)?
  4. What is the value of f(3+h)f(3)h\frac{f(3+h) - f(3)}{h} when h=1h = 1?
  5. How would the solution change if f(x)f(x) were x25x^2 - 5 instead of x2+5x^2 + 5?

Tip: Expressions like f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} are fundamental in calculus, as they form the basis for understanding derivatives.

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Math Problem Analysis

Mathematical Concepts

Function evaluation
Quadratic functions
Difference quotient

Formulas

Quadratic function formula f(x) = x^2 + 5
Difference quotient formula \( \frac{f(x+h) - f(x)}{h} \)

Theorems

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Suitable Grade Level

Grades 10-12