S = πr(r + √(h² + r²))
400.2 = 3.14(6)(6 + √(h² + 6²))
400.2 = 18.84(6 + √(h² + 36))
18.84 18.84
21¹⁰⁹/₄₇₁ = 6 + √(h² + 36))
- 6 - 6
15¹⁰⁹/₄₇₁ = √(h² + 36)
231²²¹⁰⁰⁵/₂₂₁₈₄₁ = h² + 36
- 36 - 36
195²²¹⁰⁰⁵/₂₂₁₈₄₁ = h²
14 ≈ h
Answer:
a) Y(x) = {900, x≤30; 900-40(x-30), x>30}
b) T(x) = {900x, x≤30; 2100x-40x², x>30}
c) dT/dx = {900, x≤30; 2100-80x, x>30}
Step-by-step explanation:
a) The problem statement gives the function for x ≤ 30, and gives an example of evaluating the function for x = 35. So, replacing 35 in the example with x gives the function definition for x > 30.

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b) The yield per acre is the product of the number of trees and the yield per tree:
T(x) = x·Y(x)

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c) The derivative is ...

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The attached graph shows the yield per acre (purple, overlaid by red for x<30), the total yield (black), and the derivative of the total yield (red). You will note the discontinuity in the derivative at x=30, where adding one more tree per acre suddenly makes the rate of change of yield be negative.
Answer: 32 pints
Explanation:
.16 x 25 = 4 gallons convert to pints
1 gallon is equal to 8 pints so 4 x 8 = 32 pints