[x^(1/4)+y^(1/4)]²

　　=[x^(1/4)]²+2x^(1/4)y^(1/4)+[y^(1/4)]²

　　=x^(1/2)+2x^(1/4)y^(1/4)+y^(1/2)

　　==不好意思，我问错了，是它的1/2怎么算

　　[x^(1/4)+y^(1/4)]^(1/2)无法算只能出将其化成根式的题目[x^(1/4)+y^(1/4)]^(1/2)=√(⁴√x+⁴√y)已经是最简的根式了

　　这样啊TT那如果已知a(1/2)+a(-1/2)=3,a(1/4)+a(-1/4)怎么算，拜托了，数学老师没上到这却布置了这个作业，明天上交，解好再追加10分

　　∵a(1/2)+a(-1/2)=3,∴[a(1/4)+a(-1/4)]²=a(1/2)+2+a(-1/2)=3+2=5又a(1/4)+a(-1/4)>0a(1/4)+a(-1/4)=√5