化简cosA*cos2A*cos4A……cos2^nA
问题描述:
化简cosA*cos2A*cos4A……cos2^nA
答
cosA*cos2A*cos4A……cos2^nA =sinA*cosA*cos2A*cos4A……cos2^nA/sinA =sin2A*cos2A*cos4A……cos2^nA/2sinA =sin4A……cos2^nA/4sinA =sin2^(n+1)A/[2^(n+1)sinA]