答:
f(x)=cos1.5xcos0.5x-sin1.5xsin0.5x
-2p根号[(cos1.5x+cos0.5x)2+(sin1.5x-sin0.5x)2]
=cos2x-2p根号(2+2cos2x)
=2cos2x-1-2p*2(cosx)
二倍角公式,()表示绝对值
=2{[(cosx-p)]2-1-4p2
当p>1时,x=0,f(x)最小
1-4p=-3/2,p=5/8,不合题意
当p
答:
f(x)=cos1.5xcos0.5x-sin1.5xsin0.5x
-2p根号[(cos1.5x+cos0.5x)2+(sin1.5x-sin0.5x)2]
=cos2x-2p根号(2+2cos2x)
=2cos2x-1-2p*2(cosx)
二倍角公式,()表示绝对值
=2{[(cosx-p)]2-1-4p2
当p>1时,x=0,f(x)最小
1-4p=-3/2,p=5/8,不合题意
当p