How Is the Derivative of e^(i*theta) Derived?

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Going through the steps, we get:$\displaystyle \begin{align*} \frac{\mathrm{d}}{\mathrm{d}t} \left( \mathrm{e}^{i\theta} \right) &= \frac{\mathrm{d}}{\mathrm{d}t} \left( \cos \theta + i\sin \theta \right) \\ &= -\sin \theta + i\cos \theta \\ &= i\left( \cos \theta + i\sin \theta \right) \\ &= i\,\mathrm{e}^{i\theta} \end{align*}$Therefore, $\displaystyle \begin{align*} \Delta \left( \mathrm{
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E01
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I have a fairly simple question. My teacher used the fact that $\Delta e^{i\theta} = e^{i\theta}i\Delta \theta$ when theta approaches 0. Does he derive this using the fact that the derivate of $e^t = te^t$ ?
 
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E01 said:
I have a fairly simple question. My teacher used the fact that $\Delta e^{i\theta} = e^{i\theta}i\Delta \theta$ when theta approaches 0. Does he derive this using the fact that the derivate of $e^t = te^t$ ?

Well, first of all, $\displaystyle \begin{align*} \frac{\mathrm{d}}{\mathrm{d}t} \left( \mathrm{e}^t \right) = \mathrm{e}^t \end{align*}$, NOT $\displaystyle \begin{align*} t\,\mathrm{e}^t \end{align*}$.

What your teacher has done is use the Chain Rule.
 

FAQ: How Is the Derivative of e^(i*theta) Derived?

What does e^(iθ) represent?

e^(iθ) is a mathematical expression that represents a complex number with a magnitude of 1 and an angle of θ radians on the complex plane. It is also known as the unit complex number or the complex exponential function.

What is the significance of e^(iθ) in mathematics?

e^(iθ) is significant in mathematics because it relates three fundamental mathematical constants - e, θ, and i (the imaginary unit). It also has applications in various areas of mathematics, including calculus, trigonometry, and complex analysis.

How is e^(iθ) related to trigonometric functions?

e^(iθ) can be expressed in terms of trigonometric functions, specifically cosine and sine. It follows the Euler's formula e^(iθ) = cos(θ) + i*sin(θ), where cos(θ) represents the horizontal component (real part) and sin(θ) represents the vertical component (imaginary part) of the complex number on the unit circle.

Can e^(iθ) be used to solve equations involving complex numbers?

Yes, e^(iθ) is a powerful tool for solving equations involving complex numbers. It allows for the conversion of complex numbers into polar form, making it easier to perform mathematical operations on them.

What is the geometric interpretation of e^(iθ)?

The geometric interpretation of e^(iθ) is a point on the unit circle with a counterclockwise angle of θ radians from the positive x-axis. This point can also be represented as the intersection of a line from the origin to the point (1, θ) on the complex plane.

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