1.sin115°=sin(90°+25°)=cos25°2.cos95°=cos(90°+5°)=-sin5°3.cosπ/5+cos2π/5+cos3π/5+cos4π/5=cosπ/5+cos2π/5+cos(π-2π/5)+cos(π-π/5)=cosπ/5+cos2π/5-cos2π/5-cosπ/5=04.tan10°+tan170°+sin1866°-sin（-606°）=tan10°+tan(180°-10°)+sin(5*360°+66°)+sin(540°+66°)=tan10°-tan10°+sin66°-sin66°=05.sin（-α-5π）×cos（α-π°/2）-tan（α-3π/2）×tan（2π-α）=-sin(5π+α)cos(π/2-α)+tan(3π/2-α)tan(-α)=-sin(π+α)sinα-cotαtanα=(sinα)^2-1=-(cosα)^2

　　亲，这是选择题么