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cosA+cos(12 0^(@)+A)+cos(12 0^(@)-A)=...

`cosA+cos(12 0^(@)+A)+cos(12 0^(@)-A)=`

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To solve the expression \( \cos A + \cos(120^\circ + A) + \cos(120^\circ - A) \), we can use the cosine addition and subtraction formulas. Here’s a step-by-step breakdown of the solution: ### Step 1: Write down the expression We start with the expression: \[ \cos A + \cos(120^\circ + A) + \cos(120^\circ - A) \] ...
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