Local vs Global Behavior Math Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

easy
For p(x)=x4โˆ’100x2+1p(x) = x^4 - 100x^2 + 1, which term dominates (a) near x=0x=0 and (b) for โˆฃxโˆฃ=1000|x| = 1000?

Solution

  1. 1
    Near x=0x=0: the constant term 11 dominates since x4x^4 and x2x^2 are both tiny. p(0)=1p(0)=1; p(0.01)โ‰ˆ1โˆ’0.01=0.99p(0.01)\approx1-0.01=0.99 (approximately 11).
  2. 2
    For โˆฃxโˆฃ=1000|x|=1000: x4=1012x^4=10^{12} vastly exceeds 100x2=108100x^2=10^8. The x4x^4 term dominates. p(1000)โ‰ˆ1012p(1000)\approx10^{12}.

Answer

Near x=0x=0: constant term 11 dominates; for โˆฃxโˆฃ=1000|x|=1000: x4x^4 term dominates
In polynomials, the dominant term depends on the scale: near the origin, lower-degree terms matter; for large โˆฃxโˆฃ|x|, the highest-degree term overwhelms all others.

About Local vs Global Behavior

Local behavior describes a function's properties near a specific point; global behavior describes its overall properties across the entire domain or as inputs grow without bound.

Learn more about Local vs Global Behavior โ†’

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