Un = cos^n thita + sin^n thita. 2U6 - 3U4 is equal to?? (a) 0 (b) 1 (c) -1 (d) none of these (U4-U2)^2 is equal to ??? (a)1/4sin^4 2thita (b)sin^4 2thita (c)4sin^4 2thita (d) none of these Share with your friends Share 10 Lovina Kansal answered this Dear student Given: Un=sinnθ+cosnθThen 2U6-3U4=2sin6θ+cos6θ-3sin4θ+cos4θ=sin4θ2sin2θ-3+cos4θ2cos2θ-3=sin4θ2sin2θ-2-1+cos4θ2cos2θ-2-1=sin4θ-21-sin2θ-1+cos4θ-21-cos2θ-1=sin4θ-2cos2θ-1+cos4θ-2sin2θ-1=-2sin4θcos2θ+sin4θ+2cos4θsin2θ-cos4θ=-sin4θ+cos4θ+2sin2θ cos2θsin2θ+cos4θ=-sin2θ2+cos2θ2+2sin2θ cos2θ=-sin2θ+cos2θ=-1 Regards 6 View Full Answer