1.已知f(x)是偶函数,g(x)是奇函数,且f(x)+g(x）=x²+x-2,求f(x),g(x）的表达式.

f(x)+g(x) = x²+x-2
将x=-x带入得
f(x)-g(x) = x²-x-2
两式相加并化简得
f(x) = x² - 2
带入原式得
g(x) = x