新定义一种运算a△b=(a+b)/(1-ab),求(-2)△(-1/3)的值
问题描述:
新定义一种运算a△b=(a+b)/(1-ab),求(-2)△(-1/3)的值
答
(-2)△(-1/3)
= [-2 + (-1/3)]/[1-(-2)(-1/3)]
= (-7/3)/(1-2/3)
= (-7/3)/(1/3)
= -7