Solve cosx^4-sinx^4: Confirm My Answer?

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AI Thread Summary
The problem involves simplifying the expression cos(x)^4 - sin(x)^4. The correct simplification is cos(2x), which is confirmed by multiple participants in the discussion. They suggest that the solution can be derived quickly by factoring the difference of squares. Familiarity with trigonometric identities is emphasized as essential for solving such problems. The consensus is that cos(2x) is indeed the correct answer.
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Homework Statement


simplify cosx4-sinx4


The Attempt at a Solution



I got cos2x

does anybody want to solve this and let me know if I am right ?
 
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Cos2x is correct.
 
synergix said:

Homework Statement


simplify cosx4-sinx4


The Attempt at a Solution



I got cos2x

does anybody want to solve this and let me know if I am right ?

Hi synergix! :smile:

It's obviously cos2x :biggrin: …

if you're not sure, then either you didn't go the quick way (factorise a4 - b4 :wink:), or you're not familiar enough with your trignonometric identities :smile:
 

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