A 5-meter ladder is sliding down a vertical wall so the distance between the bottom of the ladder and the wall is increasing at 6 meters per minute.At a certain instant, the top of the ladder is 3 meters from the ground.What is the rate of change of the area formed by the ladder at that instant (in square meters per minute)?Choose 1 answer:(A) −7(B) 6(C) 18(D) −14
Q. A 5-meter ladder is sliding down a vertical wall so the distance between the bottom of the ladder and the wall is increasing at 6 meters per minute.At a certain instant, the top of the ladder is 3 meters from the ground.What is the rate of change of the area formed by the ladder at that instant (in square meters per minute)?Choose 1 answer:(A) −7(B) 6(C) 18(D) −14
Triangle Information: The ladder, wall, and ground form a right triangle. The ladder's length is the hypotenuse, and it's 5 meters long. The distance from the top of the ladder to the ground is 3 meters.
Finding x: Let's call the distance from the bottom of the ladder to the wall x meters. We can use the Pythagorean theorem to find x. 52=32+x225=9+x2x2=25−9x2=16x=4 meters.
Calculating Area: The area A of the triangle at that instant is (1/2)×base×height=(1/2)×x×3.A=(1/2)×4×3A=6 square meters.
Rate of Change: The rate of change of x is given as 6 meters per minute. We need to find the rate of change of the area, dtdA.dtdA=21⋅dtd(x⋅3)dtdA=21⋅3⋅dtdxdtdA=21⋅3⋅6dtdA=9 square meters per minute.
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