若tanx=2,求:sin(tt/2+x)*cos(tt/2-x)*tan(-x+3tt)/sin(7tt-x)*tan(6tt-x)tt 表示 “派”
问题描述:
若tanx=2,求:sin(tt/2+x)*cos(tt/2-x)*tan(-x+3tt)/sin(7tt-x)*tan(6tt-x)
tt 表示 “派”
答
sin(tt/2+x)*cos(tt/2-x)*tan(-x+3tt)/sin(7tt-x)*tan(6tt-x)
=-cosx*sinx*(-tanx)/sinx*(-tanx)
=-cosx*tanx*tanx
=-4*(根号5)/5
或者=4*(根号5)/5