### 4.3 Exponential Decay

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• Math Help

Note in Example 2 that n represents the height (in thousands of feet) and not elapsed time. The relationship between the height and atmospheric pressure, however, can be modeled by the formula for exponential decay. Also, because n is the height in thousands of feet, be sure you understand that n = 35 corresponds to a height of 35,000 feet.

• Consumer Suggestion

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• Checkpoint Solution

The formula for this exponential decay is

At 14,000 feet, the atmospheric pressure is

At 20,320 feet, the atmospheric pressure is

So, the atmospheric pressure decreases by about atmosphere as you climb from 14,000 to 20,320 feet.

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