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secondary 4 | E Maths
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How to do the working
Date Posted: 5 years ago
Views: 379
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8 sin^2 x + 2 cos^2 x
= 6 sin^2 x + 2 sin^2 x + 2 cos^2 x
= 6 sin^2 x + 2 (sin^2 x + cos^2 x)
= 6 sin^2 x + 2
= 6 * 0.5 * (1 - cos 2x) + 2 (using a rearranged double angle formula for cos 2x)
= 3 - 3 cos 2x + 2
= 5 - 3 cos 2x
Amplitude is 3 (not -3) and period 360 deg / 2 = 180 deg (or 2pi/2 = pi if the question is in radian mode).
Maximum is 8 when cos 2x equals -1 and minimum is 2 when cos 2x equals 1.
= 6 sin^2 x + 2 sin^2 x + 2 cos^2 x
= 6 sin^2 x + 2 (sin^2 x + cos^2 x)
= 6 sin^2 x + 2
= 6 * 0.5 * (1 - cos 2x) + 2 (using a rearranged double angle formula for cos 2x)
= 3 - 3 cos 2x + 2
= 5 - 3 cos 2x
Amplitude is 3 (not -3) and period 360 deg / 2 = 180 deg (or 2pi/2 = pi if the question is in radian mode).
Maximum is 8 when cos 2x equals -1 and minimum is 2 when cos 2x equals 1.
See 2 Answers
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This is also possible, amongst several methods.
Date Posted:
5 years ago
done
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Hope this helps, impt parts in pink
Date Posted:
5 years ago
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