1-2sin 22.5°

计算：sin²1°+sin²2°+sin²3°...+sin²45°+sin&# 数列求和 sin²1°+sin²2°+sin²3°+.+sin²88°+sin& sin²1°+sin²2°+sin²89°+sin²88°= sin²1°+sin²2°+……sin²88°+sin²89° sin^2 (0°)+sin^2( 1°)+.+sin^2(90du) 求和 在mathematica里输入Plot[Sin[x] Sin[x + 2] - Sin[x + 1]Sin[x + 1] 求证:sin^2/(sin-cos) - (sin+cos)/(tan^2 -1) =sin+cos 计算1-2sin(sin上面有个小2)22.5(22.5上面有个小零)等于多少? 求证sin3°=（sin^2°-sin^1°）/sin1° 计算[3/(sin^2)20°-[1/(cos^2)20°]+64(sin^2)20° 在Rt△ABC中,角C=90°,求证sin^2A+sin^2B=1,并利用上式求sin^21°+sin^22°+sin^ 证明：(1) sin(360°-α)=-sinα