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Ch. 1 - Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 1, Problem 1.4

A hot-air balloon rising straight up from a level field is tracked by a range finder located 500 ft from the point of liftoff. Express the balloon’s height as a function of the angle the line from the range finder to the balloon makes with the ground.

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1
Consider the right triangle formed by the balloon, the range finder, and the point on the ground directly below the balloon. The balloon's height is the opposite side, the distance from the range finder to the point of liftoff is the adjacent side, and the line from the range finder to the balloon is the hypotenuse.
Let \( \theta \) be the angle between the ground and the line from the range finder to the balloon. We need to express the balloon's height \( h \) as a function of \( \theta \).
Use the tangent function, which relates the opposite side to the adjacent side in a right triangle: \( \tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} = \frac{h}{500} \).
Solve for \( h \) in terms of \( \theta \): \( h = 500 \cdot \tan(\theta) \).
Thus, the balloon's height as a function of the angle \( \theta \) is \( h(\theta) = 500 \cdot \tan(\theta) \).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Trigonometric Functions

Trigonometric functions, such as sine, cosine, and tangent, relate the angles of a triangle to the lengths of its sides. In this context, the height of the balloon can be expressed using the tangent function, which connects the angle of elevation from the range finder to the height of the balloon and the horizontal distance from the range finder to the point of liftoff.
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Right Triangle Relationships

The scenario involves a right triangle formed by the height of the balloon, the horizontal distance from the range finder to the liftoff point, and the line of sight to the balloon. Understanding the properties of right triangles is essential for applying trigonometric ratios to find the height of the balloon as a function of the angle of elevation.
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Function Representation

In calculus, expressing one quantity as a function of another is fundamental. Here, the height of the balloon is represented as a function of the angle of elevation, allowing for the analysis of how changes in the angle affect the height. This relationship can be modeled mathematically, facilitating further exploration of the balloon's motion.
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