Express cos^6(x) without Powers of Trig Functions

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SUMMARY

The discussion focuses on expressing cos6(x) without using powers of trigonometric functions. The solution begins by rewriting cos6(x) as (cos2(x))3 and then transforming it into ((cos(2x) + 1)/2)3. The expansion results in the expression 1/8 + 3/8 cos(2x) + 3/8 cos2(2x) + 1/8 cos3(2x). Further simplification is required to eliminate powers entirely, specifically by applying techniques similar to those used for cos(2x).

PREREQUISITES
  • Understanding of trigonometric identities, specifically cos(2x)
  • Familiarity with algebraic expansion techniques
  • Knowledge of the binomial theorem
  • Ability to manipulate trigonometric functions without powers
NEXT STEPS
  • Learn how to simplify cos2(2x) using trigonometric identities
  • Study the binomial theorem for polynomial expansions
  • Explore advanced trigonometric identities for expressing powers
  • Investigate techniques for eliminating powers in trigonometric expressions
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Students studying trigonometry, mathematics educators, and anyone looking to deepen their understanding of trigonometric function manipulation.

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Homework Statement


Express cos^6(x) in a form that does not involve powers of trig functions


Homework Equations



idk actually...binomial theorem? algebra? lol


The Attempt at a Solution



ok, so i realized that it can be expressed as (cos^2(x))^3

and that can be ((cos(2x) + 1)/2)^3

and that can be expanded as

1/8+3/8 cos(2 x)+3/8 cos^2(2 x)+1/8 cos^3(2 x)

but how do i get the answer with no powers in in? idk what to do up until that point
 
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You already showed how to handle cos2(x). Do a similar thing with cos2(2x).
 

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