sin10sin30sin50sin70=

求值：sin10sin30sin50sin70 化简sin10sin30sin50sin70 sin10sin30sin50sin70= sin10sin30sin50sin70 求值 sin10sin30sin50sin70=多少 sin10sin30sin50sin70的值 求sin10sin30sin50sin70的值 求sin10sin30sin50sin70的值 sin10sin30sin50sin70的值= (是度）答案是1/16 我要过程 求sin10sin30sin50sin70的值(最好有过程),还有的就是sin20sin60sin100sin140=cos10cos30cos50cos70吗? (1/2)求值,1.sin10sin30sin50sin70 2.(2cos10-sin20)/cos20 3.(1+cos20)/2sin20 sin10sin30sin50sin70 =1/2sin1sin10sin30sin50sin70=1/2sin10sin50sin70=1/2sin10cos20cos40=1/2cos10cos10cos20cos40/cos10=1/4sin20cos20cos40/cos10=1/8sin40cos40/cos10=1/16sin80/cos10=1/16cos10/cos10=1/16第一步到第二步sim50sin70怎么变成了cos20