设实数p=三次根号4-三次根号6+三次根号9,求证1
问题描述:
设实数p=三次根号4-三次根号6+三次根号9,求证1
答
p=2^(2/3)-2^(1/3)*3^(1/3)+3^(2/3)=5/(2^(1/3)+3^(1/3))
注:a^2-ab+b^2=(a^3+b^3)/(a+b)
所以只需证2.5