Math Problem Statement
The volume of a cube is increasing at the rate of 6cm3/s. How fast is the surface 2 area of cube increasing, when the length of an edge is cm?
Solution
To solve this, we need to use related rates involving the volume and surface area of a cube. Let be the length of an edge of the cube (in cm), the volume, and the surface area.
Step 1: Relations for Volume and Surface Area
- The volume of a cube is given by:
- The surface area of a cube is given by:
Step 2: Differentiating Volume and Surface Area with Respect to Time
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Differentiate the volume equation with respect to time : We are given that .
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Differentiate the surface area equation with respect to time :
Step 3: Solve for
Using the equation from the volume: Solve for :
Step 4: Substitute into the Surface Area Equation
Now, substitute into the equation for :
So, the rate at which the surface area is increasing is:
Final Answer:
The surface area is increasing at the rate of when the edge length is cm.
Would you like to go over any step in more detail, or explore some variations of this problem?
Here are 5 related questions:
- What happens if the rate of change of the volume was different?
- How would the problem change if the shape were a sphere?
- What is the rate of change of the diagonal of the cube?
- How fast is the edge length increasing when the surface area is increasing at 10 cm²/s?
- How does the surface area change when the edge is doubled?
Tip: When solving related rates problems, make sure to differentiate each variable with respect to time carefully!
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Math Problem Analysis
Mathematical Concepts
Geometry
Related Rates
Differentiation
Formulas
Volume of a cube: V = x^3
Surface area of a cube: A = 6x^2
Rate of change of volume: dV/dt = 3x^2 (dx/dt)
Rate of change of surface area: dA/dt = 12x (dx/dt)
Theorems
Related Rates Theorem
Differentiation with Respect to Time
Suitable Grade Level
Grades 11-12
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