Why is My TI-89 Not Evaluating the Fourier Transform Correctly?

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SUMMARY

The TI-89 calculator fails to evaluate the Fourier transform correctly due to the angle mode setting. Users must ensure the calculator is set to radian mode to utilize Euler's identity effectively. When encountering a "Domain Error" with the expression Integral(x*e^(-i*2*pi*f*t),t), switching to radians resolves the issue. This adjustment is crucial for accurate calculations involving trigonometric functions in Fourier transforms.

PREREQUISITES
  • Understanding of Fourier transforms
  • Familiarity with Euler's identity
  • Knowledge of TI-89 calculator settings
  • Basic proficiency in complex numbers and integrals
NEXT STEPS
  • Learn how to set angle modes on the TI-89 calculator
  • Explore advanced applications of Fourier transforms in signal processing
  • Study the implications of Euler's identity in complex analysis
  • Investigate common errors in TI-89 calculations and their solutions
USEFUL FOR

Students, engineers, and mathematicians who utilize the TI-89 calculator for complex calculations, particularly in signal processing and Fourier analysis.

Samuelcomeau
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TL;DR
My TI-89 is not evaluating the Fourier transform? Change angle to radians and retry.
Summary:: My TI-89 is not evaluating the Fourier transform? Change angle to radians and retry.

Hello, I discovered this forum trying to answer the question: Why is my TI-89 not properly evaluating the Fourier transform? I found no answer, by chance I experimented and found that the calculator must be in radian mode to make proper use of Eulers identity.
So if Integral(x*e^(-i*2*pi*f*t),t) gives the error: Domain Error. Then change your units to radians in the mode menu. Have a nice day.
 
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:welcome: Samuel. Good to have you here!

Samuelcomeau said:
Summary:: My TI-89 is not evaluating the Fourier transform? Change angle to radians and retry.

Integral(x*e^(-i*2*pi*f*t),t) gives the error: Domain Error.
Yeah, that "2*pi" term is a giveaway that it thinks in radians. Keep that in mind for future applications. :wink:

Cheers,
Tom
 

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