The side of the base of a square prism is decreasing at a rate of 7 kilometers per minute and the height of the prism is increasing at a rate of 10 kilometers per minute.At a certain instant, the base's side is 4 kilometers and the height is 9 kilometers.What is the rate of change of the surface area of the prism at that instant (in square kilometers per minute)?Choose 1 answer:(A) 148(B) −204(C) −148(D) 204The surface area of a square prism with base side s and height h is 2s2+4sh.
Q. The side of the base of a square prism is decreasing at a rate of 7 kilometers per minute and the height of the prism is increasing at a rate of 10 kilometers per minute.At a certain instant, the base's side is 4 kilometers and the height is 9 kilometers.What is the rate of change of the surface area of the prism at that instant (in square kilometers per minute)?Choose 1 answer:(A) 148(B) −204(C) −148(D) 204The surface area of a square prism with base side s and height h is 2s2+4sh.
Formula Explanation: The surface area (SA) of a square prism is given by the formula SA=2s2+4sh, where s is the side of the base and h is the height.
Chain Rule Application: We need to find the rate of change of the surface area with respect to time, which is dtd(SA).
Derivative Calculations: To find dtd(SA), we'll use the chain rule from calculus: dtd(SA)=dsd(SA)⋅dtds+dhd(SA)⋅dtdh.
Rate of Change Calculation: First, we calculate dsd(SA)=4s+4h, since the derivative of s2 with respect to s is 2s and the derivative of sh with respect to s is h.
Substitution of Values: Next, we calculate dhd(SA)=4s, since the derivative of sh with respect to h is s and the derivative of s2 with respect to h is 0.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7 km/min and 10 km/min, respectively.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively.We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively. We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively. So, dtd(SA)=(4s+4h)(−7)+(4s)(10).
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively. We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively. So, dtd(SA)=(4s+4h)(−7)+(4s)(10). Substitute s=4 and dtdh0 into the equation: dtdh1.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively. We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively. So, dtd(SA)=(4s+4h)(−7)+(4s)(10). Substitute s=4 and dtdh0 into the equation: dtdh1. Simplify the equation: dtdh2.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively. We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively. So, dtd(SA)=(4s+4h)(−7)+(4s)(10). Substitute s=4 and dtdh0 into the equation: dtdh1. Simplify the equation: dtdh2. Calculate the values: dtdh3.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively. We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively. So, dtd(SA)=(4s+4h)(−7)+(4s)(10). Substitute s=4 and dtdh0 into the equation: dtdh1. Simplify the equation: dtdh2. Calculate the values: dtdh3. dtdh4.
Final Calculation: Now we plug in the values for dtds and dtdh, which are −7km/min and 10km/min, respectively. We also plug in the values for s and h at the given instant, which are 4km and 9km, respectively. So, dtd(SA)=(4s+4h)(−7)+(4s)(10). Substitute s=4 and dtdh0 into the equation: dtdh1. Simplify the equation: dtdh2. Calculate the values: dtdh3. dtdh4. Finally, dtdh5 square kilometers per minute.
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