Stitz-Zeager_College_Algebra_e-book

A r 0 r 6 sin 2 b r 0 r 3 3 cos

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Unformatted text preview: ) and C (b, 0). From Theorem 10.3, we know that since the point B (x, y ) lies on a circle of radius c, the coordinates of B are B (x, y ) = B (c cos(α), c sin(α)). (This would be true even if α were an obtuse or right angle so although we have drawn the case when α is acute, the following computations hold for any angle α drawn in standard position where 0 < α < 180◦ .) We note that the distance between the points B and C is none other than the length of side a. Using the distance formula, Equation 1.1, we get 1 Here, ‘Side-Angle-Side’ means that we are given two sides and the ‘included’ angle - that is, the given angle is adjacent to both of the given sides. 774 Applications of Trigonometry a= a2 = (c cos(α) − b)2 + (c sin(α) − 0)2 (c cos(α) − b)2 + c2 sin2 (α) 2 a2 = (c cos(α) − b)2 + c2 sin2 (α) a2 = c2 cos2 (α) − 2bc cos(α) + b2 + c2 sin2 (α) a2 = c2 cos2 (α) + sin2 (α) + b2 − 2bc cos(α) a2 = c2 (1) + b2 − 2bc cos(α) Since cos2 (α) + sin2 (α) = 1 a2 = c...
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This note was uploaded on 05/03/2013 for the course MATH Algebra taught by Professor Wong during the Fall '13 term at Chicago Academy High School.

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