Question
Sat May 19, 2012 By: Vaishnavi Sankeet

cosA+cossquareA = 1 then find, sinsquaredA + sinwithdegree4A

Expert Reply
Sun May 20, 2012
cosA+cos2A = 1 (i)
So, cosA = 1-cos2A = sin2A       (ii)
Now, sin2A + sin4A = sin2A(1+sin2A)
                            =  cosA (1+cosA)        [Using (ii)]
                            = cosA+cos2A = 1        [Using (i)]
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