您好：解答如下17π/12得到cos(π/4 +x)=3/5，sin(π/4 +x)=-4/5cosx=cos(π/4 +x-π/4 ) =cos(π/4 +x)cosπ/4+sin(π/4 +x)sinπ/4 =3/5×√2/2+（-4/5）×√2/2 =-√2/10因为17π/12sin2x=2sinxcosx=7/25(sin2x+2sin²x)/1-tanx=（7/25+49/25）/（1-7）=-28/75谢谢采纳，有疑问欢迎您追问
