sin130度的平方再加sin70度乘con80度等于多少

解：sin130°×sin130°+sin70°×cos80°
=sin50°×sin50°+cos20°×sin10°
=sin(30°+20°)×sin(60°-10°)+cos20°×sin10°
=(sin30°×cos20°+cos30°×sin20°)×(sin60°×cos10°-cos60°×sin10°)+cos20°×sin10°
={(1/2)×cos20°+[(√3)/2]×sin20°}×{[(√3)/2]×cos10°-(1/2)×sin10°}+cos20°×sin10°
=(√3/4)cos20°cos10°-(1/4)cos20°sin10°+(3/4)sin20°cos10°-(√3/4)sin20°sin10°+cos20°sin10°
=(√3/4)×cos20°×cos10°-(√3/4)×sin20°×sin10°+(3/4)×sin20°×cos10°+(3/4)×cos20°×sin10°
=(√3/4)×(cos20°×cos10°-sin20°×sin10°)+(3/4)×(sin20°×cos10°+cos20°×sin10°)
=(√3/4)×cos(20°+10°)+(3/4)×sin(20°+10°)
=(√3/4)×cos30°+(3/4)×sin30°
=(√3/4)×(√3/2)+(3/4)×(1/2)
=3/8+3/8
=3/4
纯手打，原创作品，如有不懂的地方，欢迎随时追问!

有那么懒吗？计算器按不就搞定了。。。