Current location - Training Enrollment Network - Mathematics courses - How to do the ninth question of the national volume of liberal arts in the 2007 mathematics college entrance examination?
How to do the ninth question of the national volume of liberal arts in the 2007 mathematics college entrance examination?
B
Adequacy: f (x) = f (-x); g(x)= g(-x)；
h(x)=f(x)+g(x)
= f(-x)+g(-x)= h(-x)；
Necessity: h(x)=h(-x)=f(x)+g(x)
=f(-x)+g(-x)
F (x) = f (-x) may not be derived;
g(x)= g(-x)； Because f (x) = g (-x) can also be deduced; g(x)= f(-x)；