x,lg y,lg z,lg(x+y)、1g(x-y)表示 lg(x^2-y^2)
问题描述:
x,lg y,lg z,lg(x+y)、1g(x-y)表示 lg(x^2-y^2)
答
lg(x^2-y^2)
=lg[(x+y)(x-y)]
=lg(x+y)+1g(x-y)