解sin70°(sin25+cos25°)
=sin70°√2(√2/2sin25+√2/2cos25°)
=sin70°√2(cos45°sin25+sin45°cos25°)
=sin70°√2sin(45°+25°)
=√2sin70°sin70°
=√2sin²70°
解sin70°(sin25+cos25°)
=sin70°√2(√2/2sin25+√2/2cos25°)
=sin70°√2(cos45°sin25+sin45°cos25°)
=sin70°√2sin(45°+25°)
=√2sin70°sin70°
=√2sin²70°