Differentiate and simplify: f(x)=sin^2(2x)-cos^2(2x)

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SUMMARY

The expression f(x) = sin²(2x) - cos²(2x) has been fully simplified to y = -cos(4x). This conclusion is supported by the application of the trigonometric identity cos(2θ) = cos²(θ) - sin²(θ). Participants in the discussion agree that while various trigonometric identities can be applied, the derived expression is the simplest form achievable for this function.

PREREQUISITES
  • Understanding of trigonometric identities, specifically cos(2θ) = cos²(θ) - sin²(θ)
  • Familiarity with the sine and cosine functions
  • Basic knowledge of function simplification techniques
  • Ability to manipulate and transform trigonometric expressions
NEXT STEPS
  • Study advanced trigonometric identities and their applications
  • Learn about function transformations in trigonometry
  • Explore the implications of simplifying trigonometric expressions in calculus
  • Investigate the graphical representation of trigonometric functions and their transformations
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Students studying trigonometry, mathematics educators, and anyone interested in simplifying trigonometric expressions and understanding their applications in various mathematical contexts.

ttpp1124
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Homework Statement
Has this been simplified fully?
Relevant Equations
n/a
Screen Shot 2020-05-11 at 10.11.17 PM.png
 
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ttpp1124 said:
Homework Statement:: Has this been simplified fully?
Relevant Equations:: n/a

View attachment 262618
Do you have a question here?
 
Is that an answer to the quesion in post #1 or the one in post #2 ? Or both ? :cool:

Let me ask @ttpp1124 : do you expect there exists a simpler expression ? In what way ?
 
Last edited:
yes, it is fully simplified, and of course with trig you could go in many circles with identities but I believe the one stopped at is simplest.
 
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Mark44 said:
Do you have a question here?
yes, sorry, I forgot to include the question! here it is:
 

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I would use \cos (2\theta) = \cos^2 \theta - \sin^2\theta, from which immediately y = -\cos(4x).
 
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ttpp1124 said:
yes, sorry, I forgot to include the question! here it is:
Not much of a question !

Kudos @pasmith : the simplest path to the simplest result !
 

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