Convert sums a cos(x) + b sin(x) to R cos(x ± α) or R sin(x ± α) and apply these to sketch graphs.

u2-t4-s3-d4

Interactive

a cos x + b sin x as R cos(x − α)

manipulative

Scrub x so dots trace a cos x and b sin x on the top plane; the matching single sinusoid of amplitude R sits on a second plane below.

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