11.10
Some functions are bounded between two other functions, which determine their limiting value.
The Squeeze Theorem applies when a function remains bounded between two other functions over an interval, usually denoted by I, near a point, and both bounding functions approach the same value. Within that interval, the function constrained between them must also share that limit.
This creates a narrowing pathway, keeping the inner curve trapped between the other two functions near a specific point.
Consider the function x² times the cosine of 20πx.
As x approaches zero, the function converges to zero.
Since cosine is always bounded between -1 and 1, multiplying by x² makes the product oscillate within the envelopes –x² and x², regardless of its frequency.
As a result, the entire function remains between two bounding functions: –x² and x².
Both bounding functions approach zero as x approaches zero, so the middle function also approaches zero, as defined by the squeeze theorem.
This theorem also appears in engineering software, where stress estimates are bounded between upper and lower limits. With each iteration, the bounds tighten and the estimate converges.
Certain mathematical functions exhibit unpredictable or highly variable behavior near specific input values, making direct evaluation of their limits…
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