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For the total-cost function C(x)=x³−8x² +6x+50 find ΔC and C (x) when x=50 and Δx=1.

A) ΔC=$6,799;C ′ (50)=$6,706
B) ΔC=$6,849;C ′ (50)=$6,706
C) ΔC=$6,899;C ′ (50)=$6,706
D) ΔC=$6,849;C ′ (50)=$6,700

User Pam Lahoud
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1 Answer

5 votes

Final answer:

The change in cost ΔC when x changes from 50 to 51 for the function C(x) is Δ6849, and the rate of change of the cost function C'(x) at x=50 is Ζ706.

Step-by-step explanation:

The student asked to find ΔC and C'(50) when x=50 and Δx=1 for the total-cost function C(x)=x³−8x²+6x+50. To find ΔC, we evaluate the cost function at x=50 and x=51, and find the difference. To find C'(x), we first calculate the derivative of the cost function.

Step-by-Step Calculation

To compute ΔC:
C(50) = (50)³ − 8(50)² + 6(50) + 50 = 125000 − 20000 + 300 + 50 = 105350
C(51) = (51)³ − 8(51)² + 6(51) + 50 = 132651 − 20808 + 306 + 50 = 112199
ΔC = C(51) − C(50) = 112199 − 105350 = Δ6849

To compute C'(50), first find the derivative:
C'(x) = 3x² − 16x + 6
C'(50) = 3(50)² − 16(50) + 6 = 7500 − 800 + 6 = Ζ706

Therefore, the correct answer is B) ΔC=Δ6849; C'(50)=Ζ706

User Rick Buczynski
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