Complex Notation Homework: Solve for B & Phi in Terms of A, Omega, Delta

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SUMMARY

The discussion centers on solving for B and Phi in terms of A, omega, and delta from the equation x = Acos(ωt + δ) and its equivalent form x = Re(Be^{iΦ}). The key insights reveal that using Euler's formula, the relationships can be established as B = A and Φ = ωt + δ. This approach effectively utilizes the conversion between rectangular and polar forms of complex numbers to derive the necessary relationships.

PREREQUISITES
  • Understanding of complex numbers and their polar and rectangular forms
  • Familiarity with Euler's formula: e^(iφ) = cos(φ) + i*sin(φ)
  • Basic knowledge of trigonometric identities
  • Ability to manipulate algebraic equations
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  • Study the conversion techniques between rectangular and polar forms of complex numbers
  • Explore applications of Euler's formula in various mathematical contexts
  • Learn about trigonometric identities and their use in solving equations
  • Practice solving complex equations involving real and imaginary components
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Students in mathematics or engineering disciplines, particularly those studying complex numbers, trigonometry, and their applications in physics and engineering problems.

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Homework Statement



If x= Acos(\omegat + \delta), then one can also write it as x = Re(Be^{i\Phi}). Find B and \Phi in terms of A, \omega, and \delta if B is real.

Homework Equations





The Attempt at a Solution



Not sure where to start on this one. I know you guys can't give answers. All I'm looking for is where to get started. Any help would be appreciated.
 
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w3390 said:

Homework Statement



If x= Acos(\omegat + \delta), then one can also write it as x = Re(Be^{i\Phi}). Find B and \Phi in terms of A, \omega, and \delta if B is real.

Homework Equations





The Attempt at a Solution



Not sure where to start on this one. I know you guys can't give answers. All I'm looking for is where to get started. Any help would be appreciated.

Are you familiar with converting between the rectangular and polar forms of complex numbers? See partway down this wiki page:

http://en.wikipedia.org/wiki/Polar_coordinate_system

.
 
Actually, I think I might have something.

Euler's formula says: e^(i*phi) = cos(phi) + i*sin(phi)

The real part of this is: Re(e^(i*phi)) = cos(phi).

Therefore, the real part of Be^(i*phi) is: Bcos(phi).

So I have: X = Bcos(phi) and X = Acos(wt + delta)

Am I able to just compare the two equations to get the following relationships:

B = A

PHI = wt + deltaIt can't be that simple, can it?
 
w3390 said:
Actually, I think I might have something.

Euler's formula says: e^(i*phi) = cos(phi) + i*sin(phi)

The real part of this is: Re(e^(i*phi)) = cos(phi).

Therefore, the real part of Be^(i*phi) is: Bcos(phi).

So I have: X = Bcos(phi) and X = Acos(wt + delta)

Am I able to just compare the two equations to get the following relationships:

B = A

PHI = wt + delta


It can't be that simple, can it?

:biggrin:
 

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