simplify cos^2 x/4 - sin^2 x/4?

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simplify cos^2 x/4 - sin^2 x/4?

2007-03-30 09:59:22 · 3 answers · asked by jonoco 1 in Science & Mathematics ➔ Mathematics

3 answers

Use the double angle formula.

cos²(x/4) - sin²(x/4) = cos(x/2)

2007-03-30 10:22:57 · answer #1 · answered by Northstar 7 · 0⤊ 0⤋

This is the Cos 2A formula where, in this case, A = x/4. So it's Cos 2(x/4) = Cos (x/2). You could stop there, but there is also a formula for Cos (x/2) that could take you one step further (not necessarily simpler, though). It is +- sqrt [(1+cos A)/2]

2007-03-30 17:49:02 · answer #2 · answered by Kathleen K 7 · 0⤊ 0⤋

Look up cosine double angle formula.

2007-03-30 17:13:40 · answer #3 · answered by mathsmanretired 7 · 0⤊ 0⤋