In trigonometry, the Cosine Rule (also known as Law of Cosine) relates the lengths of the sides of a triangle to the cosine of one of its angles. The following are three versions of the Cosine Formula. The easiest of course to remember is the last one since it looks like the Pythagorean Formula. The…

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Problem: Prove that the equation below is an identity: 2 sin2Ө – sin4Ө = (1 – cos2Ө)(1 + cos2Ө). Solution To prove that an equation is an identity, one must show that the Left Hand Side (LHS) of the equation is identical to its Right Hand Side (RHS). That is, LHS ≡ RHS. Proof LHS: 2 sin2Ө…

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The general technique in matching trigonometric graphs and equations is to consider the intercepts, the minimum and maximum points, the shape of the prototype graph and the transformations done to the graph. Problem If 0≤x≤2π which one of the following trigonometric equations best describes this graph? A. y = 3cos 2x B. y = 2+cos…

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