Question

2cos²A + cosA-1 =0. plz plz
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Answer 1

Step-by-step explanation:

2cos2A-3cosA+1=0 2cos2A-2cosA- cosA+1=0

2cosA(cosA-1)-1(cosA-1)=0 (2cosA-1)(cosA -1)=0 (2cosA-1)=0

cosA=1/2

therefore ,

A=45 degree