Which expression can be used to find the radius of a circle with a diameter of 90 inches?
2 answers:
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Answer:
(a)
(b) Domain: <em>(See attachment for graph)</em>
(c)
Step-by-step explanation:
Given
Solving (a): A function; l in terms of w
All we need to do is make l the subject in
Divide through by 2
Subtract w from both sides
Reorder
Solving (b): The graph
In (a), we have:
Since l and w are the dimensions of the fence, they can't be less than 1
So, the domain of the function can be
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To check this
When
When
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<em>See attachment for graph</em>
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Solving (c): Write l as a function
In (a), we have:
Writing l as a function, we have:
Substitute for l in
becomes
Answer: D) Reflect over x-axis
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Explanation:
When we do this type of reflection, a point like (1,2) moves to (1,-2).
As another example, something like (5,-7) moves to (5,7)
The x coordinate stays the same but the y coordinate flips in sign from positive to negative, or vice versa.
We can say that as a general way to represent the transformation. Note how y = f(x), so when we make f(x) negative, then we're really making y negative.
If we apply this transformation to every point on f(x), then it will flip the f(x) curve over the horizontal x axis.
There's an example below in the graph. The point A(2,8) moves to B(2,-8) after applying that reflection rule.
