sinπ/8*cosπ/8

求SINπ/64 COSπ/64 COSπ/32 COSπ/16 COSπ/8 sinπ/8×cosπ/8 sinπ/8×cosπ/8 sinπ/8*cosπ/8 sinπ/8cosπ/8=( ) (cosπ/8+sinπ/8)（cos^3π/8-sin^3π/8） (cosπ/8+sinπ/8)（cos^3π/8-sin^3π/8）. (cos π/8+ sin π/8 ) (cos^3 π/8+sin^3 π/8 )的值. cos 5π/8 cos π/8 + sin 5π/8 sin π/8= 8sin(π/32)cos(π/32)cos(π/16)cos(π/8),求值 求SINπ/64 COSπ/64 COSπ/32 COSπ/16 COSπ/8!急救急救 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α-4π) cos^6(π/8)-sin^6(π/8)=求值,[cos^2(π/8)-sin^2(π/8)][cos^4(π/8)+sin^4(π/8)+cos^2(π/8)sin^2(π/8)]=cos(π/4)[1-cos^2(π/8)sin^2(π/8)]=cos(π/4)[1-[sin^2(π/4)]/4]==7√2/16 计算sin²π/8-cos²π/8= cos平方π/8-sin平方π/8, sin²π/8 -cos²π/8 sin^4π/8 +cos^4π/8 (cos(π/8))^4-(sin(π/8))^4