Solving cosz=2: A Logarithmic Approach

Thread starter kathrynag
Start date Mar 10, 2009
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Approach Logarithmic

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To solve the equation cos(z) = 2, it is essential to recognize that the cosine function does not reach values greater than 1 for real numbers, indicating a complex solution. The discussion suggests using the complex expression of cosine, which is cos(z) = (e^(iz) + e^(-iz))/2, to approach the problem. This logarithmic approach involves manipulating the equation to isolate z in terms of exponential functions. Participants emphasize the necessity of understanding complex numbers to find valid solutions. Ultimately, the equation leads to complex values for z that satisfy the original condition.

Mar 10, 2009

kathrynag

Homework Statement

Sove cosz=2

Homework Equations

The Attempt at a Solution

I need to solve this, but am not quite sure how. I was told to use log.

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Mar 11, 2009

lanedance

Homework Helper

Hi kathrynag welcome to pf

i assume you're working with complex numbers...

does the complex expression of cos help
\cos{z} = \frac{e^{iz}+e^{-iz}}{2}

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