Help with a Trigonometric identity...
Homework Statement
(sin x + sin 2x + sin 4x) / (cos x + cos 2x + cos 4x) = tan 2x
Homework Equations
sin 2x = 2sinxcosx; cos 2x = cos^2x - sin^2x
The Attempt at a Solution
solving left side,
=[sin x + sin 2x + sin (2x + 2x)]/[cos x + cos...