cos(5π/8)*cos（π/8)=

cos(π/32)*cos(π/16)*cos(π/8)= cos(5π/8)*cos（π/8)= cos^2 π/8+cos ^2 3π/8+ cos^2 5π/8+cos^2 7π/8=? cos（5π/8）*cosπ/8 化简cos^8(π/8)+cos^8(3π/8)+cos^8(5π/8)+cos^8(7π/8) 函数 (4 20:28:50)cos^4 (π /8)+cos^4(3π/8)+cos^4(5π/8)+cos^4(7π/8) = 求SINπ/64 COSπ/64 COSπ/32 COSπ/16 COSπ/8 cos(π/17)*cos(2π/17)*cos(4π/17)*cos(8π/17) cos 5π/8 cos π/8 + sin 5π/8 sin π/8= sin5π/8=cosπ/8? sinπ/8cosπ/8=( ) cos(π/12)cos(5π/12)= 2cos^2π/8-1=? cos^2-π/8-1/2=? cos²（π/8）-0.5= 不用计算器,求(cos(π/8))^4+(cos(3π/8))^4+(cos(5π/8))^4+(cos(7π/8))^4的值 0.5-cos^2(π/8) 求SINπ/64 COSπ/64 COSπ/32 COSπ/16 COSπ/8!急救急救