cos^2 80°+sin^2 50°-sin190°cos320°

sin^2 80°等于 cos^2 10°? (cos^2 10°-cos^2 80°)+sin^2 20° Sin^2 45°+cos^2 45°=? (cos^2)15°+(sin^2)15°等于多少 化简:根号1+2sin(40°)cos(40°) (cos^2)15°-(sin^2)15等于多少 化简cos^2(-α)-[tan(360°+α)/sin(-α)] sinΘ-2cosΘ=0,Θ属于（0.,90°）,求sinΘ、cosΘ的值. 求2sin(-1110°)-sin960°+根号2cos(-225°)-cos(-210°) 2cos 30°-2sin 60°·cos 45°=? 计算[3/(sin^2)20°-[1/(cos^2)20°]+64(sin^2)20° sin^2是什么,sin^260°等于什么,还有cos^43兀/2等于什么