A hovercraft takes off from a platform. Its height (in meters), x seconds after takeoff, is modeled by h(x)=−(x−11)(x+3) How many seconds after takeoff will the hovercraft land on the ground? seconds
Q. A hovercraft takes off from a platform. Its height (in meters), x seconds after takeoff, is modeled by h(x)=−(x−11)(x+3) How many seconds after takeoff will the hovercraft land on the ground? seconds
Given height function: We are given the height function h(x)=−(x−11)(x+3). To find out when the hovercraft will land on the ground, we need to determine when the height h(x) is equal to 0.
Set height function equal: Set the height function equal to zero and solve for x:0=−(x−11)(x+3)
Expand and simplify equation: Expand the equation: 0=−x2−3x+11x+33
Solve quadratic equation: Simplify the equation by combining like terms: 0=−x2+8x+33
Substitute values into formula: To find the x values when the hovercraft is on the ground, we need to solve the quadratic equation −x2+8x+33=0. This can be done by factoring, completing the square, or using the quadratic formula. Since the equation does not factor easily, we will use the quadratic formula: x=2a−b±b2−4ac, where a=−1, b=8, and c=33.
Calculate discriminant: Substitute the values of a, b, and c into the quadratic formula:x=2(−1)−8±82−4(−1)(33)
Calculate square root: Calculate the discriminant (the part under the square root):Discriminant = 82−4(−1)(33)=64+132=196
Substitute square root: Take the square root of the discriminant: 196=14
Calculate possible solutions: Substitute the square root back into the quadratic formula:x=−2−8±14
Identify meaningful solution: Calculate the two possible solutions for x:x1=−2(−8+14)=−26=−3x2=−2(−8−14)=−2−22=11
Identify meaningful solution: Calculate the two possible solutions for x:x1=(−8+14)/−2=6/−2=−3x2=(−8−14)/−2=−22/−2=11Since time cannot be negative, the solution x=−3 seconds is not physically meaningful for this problem. Therefore, the hovercraft will land on the ground 11 seconds after takeoff.
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