Question(1 point)
The area of a circular wave expands across a still pond such that its radius increases by 4 cm each second. Write a formula for the area of the circle as a function of time since the wave begins:
Studdy Solution
STEP 1
What is this asking?
We need to find a formula that tells us the area of a circular wave at any given time, knowing that the wave's radius grows by 4 cm every second.
Watch out!
Don't forget that the problem asks for the area as a function of *time*, not radius.
We'll need to connect the radius to time somehow.
STEP 2
1. Relate radius and time
2. Express area in terms of time
STEP 3
Alright, so the radius increases by cm every second.
This means that after seconds, the radius will have increased by cm.
Since the wave starts as a tiny point, we can say the **initial radius** is cm.
Therefore, the radius at any time is given by cm.
Boom!
STEP 4
We know that the area of a circle with radius is given by the formula .
This is our key to victory!
STEP 5
Now, let's **substitute** our expression for the radius in terms of time, , into the area formula.
This gives us .
We're so close, we can taste it!
STEP 6
Let's **simplify** this expression.
We have .
Fantastic!
STEP 7
The formula for the area of the circle as a function of time is .
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