Question about the argument in a Complex Exponential

In summary, the conversation discusses the use of Euler's formula to simplify the expression e^-iwx. It is suggested to use a u-substitution and remember that cos is an even function. The statement is true regardless of whether x is a real or complex number.
  • #1
Haku
30
1
Homework Statement
e^-iwt = ?
Relevant Equations
Eulers formula
I know that e^-ix = cos(-x)-isin(x), but if we have e^-iwx does that equal cos(-wx) - isin(wx)?
Thanks
 
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  • #2
Sure, why not? Just do a u-sub. Let ##u = wx## then you have ##e^{-iu} = \cos u - i\sin(u)##. Also, remember that cos is an even function, so you can drop the negative inside your argument!
 
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  • #3
If w is supposed to be a fixed complex number, you might prefer to rewrite the expression a bit before applying Euler's formula to it. But the statement is certainly true, nothing about Euler's formula requires x to be a real number to begin with.
 
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1. What is a complex exponential?

A complex exponential is a mathematical expression of the form ex + iy, where e is the base of the natural logarithm, x is the real part, and iy is the imaginary part. It is commonly used in fields such as physics, engineering, and mathematics to describe periodic or oscillatory phenomena.

2. What is the argument of a complex exponential?

The argument of a complex exponential is the value of the exponent, x + iy. It represents the angle at which the complex number is oriented in the complex plane. The argument can also be thought of as the phase of the complex exponential.

3. How is the argument of a complex exponential related to its graph?

The argument of a complex exponential determines the rotation of the graph in the complex plane. For example, if the argument is positive, the graph will rotate counterclockwise, while a negative argument will result in a clockwise rotation. The absolute value of the argument also affects the amplitude of the graph.

4. Can the argument of a complex exponential be negative?

Yes, the argument of a complex exponential can be negative. This means that the complex number is oriented in the clockwise direction in the complex plane. However, the absolute value of the argument will still determine the amplitude of the graph.

5. How is the argument of a complex exponential used in solving equations?

The argument of a complex exponential can be used to solve equations involving complex numbers. By equating the arguments of two complex exponentials, we can find the values of x and y that satisfy the equation. The argument can also be used to simplify complex expressions and solve for unknown variables.

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