diff --git a/Grade 10/Math/MPM2DZ/Trig Quiz 1.md b/Grade 10/Math/MPM2DZ/Trig Quiz 1.md index 5c4809c..e44a286 100644 --- a/Grade 10/Math/MPM2DZ/Trig Quiz 1.md +++ b/Grade 10/Math/MPM2DZ/Trig Quiz 1.md @@ -102,6 +102,9 @@ $`\cos(\beta) = \dfrac{AF}{AE} = \dfrac{AF}{1} = AF`$ $`\text{Draw a parallel line to } CD \text{ that connects point } E \text{ to } AD. \quad \cos(\alpha + \beta) = \dfrac{BE}{AE} = \dfrac{BE}{1} = BE`$ +$`\therefore \sin(\alpha + \beta) = CD = CF + FD = \cos(\alpha) \sin(\beta) + \sin(\alpha) + \cos(\beta)`$ + +$`\therefore \cos(\alpha + \beta) = BE = \cos(\alpha - \beta)`$ ## Footer Notes $`\text{ASTT} = \text{ Angle Sum Of Triangle Theorem}`$