Junior Cycle · Trigonometry
Lesson 6 of 6
JCHL Trigonometry 6: Sin(A) = Cos (90-A)
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- In a right-angled triangle the two non-right angles add up to 90°
- sin A = cos(90 − A) and cos A = sin(90 − A)
- So sin and cos of two angles that add to 90° just swap (e.g. cos 60 = sin 30)
Formula used
sin A = cos(90 - A)
cos A = sin(90 - A)
MUST LEARN
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