3tan310°+3tan20°+根号下3tan50°tan20°求值?
问题描述:
3tan310°+3tan20°+根号下3tan50°tan20°求值?
答
原式=3tan(360-50)+3tan20+√3tan50tan20=-3tan50+3tan20+√3tan50tan20tan30=tan(50-20)=(tan50-tan20)/(1+tan50tan30)=√3/3所以3tan50-3tan20=√3+√3tan50tan20所以原式=-3tan50+3tan20+√3tan50tan20=-√3...