if A=30 degree, verify that cos2A=cos^2A-sin^2A = 2cos^2A-1
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10
hi if A=30° then
Cos2A =cos^2 A - sin^2 A=2cos^2 A -1
cos 60°=cos^2 30°- sin^2 30° =2cos^2 30° -1
1/2 =(√3/2)^2 - (1/2)^2= 2(√3/2)^2 -1
1/2=3/4-1/4=2(3/4)-1
1/2=2/4=3/2 -1
1/2=1/2=1/2
hence verified
Cos2A =cos^2 A - sin^2 A=2cos^2 A -1
cos 60°=cos^2 30°- sin^2 30° =2cos^2 30° -1
1/2 =(√3/2)^2 - (1/2)^2= 2(√3/2)^2 -1
1/2=3/4-1/4=2(3/4)-1
1/2=2/4=3/2 -1
1/2=1/2=1/2
hence verified
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