C3 differentiation past-papers: mark schemes

3 + sin2x 2 cos2x Apply quotient rule: 3 + sin2x v —2 4 cos 2x Applying Any one term correct on the numerator Fully correct (unsimplified). For correct proof with an understanding thatcos22x 4 sin2 2x = l. No errors seen in working dy — 2cos2x — —2sin2x 2cos2x(2 + cos2x) — — 2sin2x(3 + sin2x) (2 + cos2x)2 ................
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