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huntingrdr
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Homework Statement
Prove the law of cosines: If a triangle has sides with lengths a, b, and c, and theta is the angle between the sides a and b, then c^2 = a^2 + b^2 - 2ab*cos(theta).
Hint: Introduce a coordinate system so that theta is in standard position. Express x and y in terms of theta and then use the distance formula to compute c.
Someone please help me on this. Not sure what is means? Thanks.
Homework Equations
The Attempt at a Solution
Don't know really where to begin or what is means.