Rule for even
[tex]\\ \sf\longmapsto \boxed{\sf f(-x)=f(x),x\in D_f}[/tex]
Rule for odd
[tex]\\ \sf\longmapsto \boxed{\sf f(-x)=-f(x),D_f}[/tex]
- Here D_f means domain of function.
#1
[tex]\\ \sf\longmapsto f(x)=\sqrt{x^2}-9[/tex]
[tex]\\ \sf\longmapsto f(4)=\sqrt{4^2}-9=4-9=-5[/tex]
[tex]\\ \sf\longmapsto f(-4)=\sqrt{(-4)^2}=4-9=-5[/tex]
Even function✓
#2
[tex]\\ \sf\longmapsto g(x)=|x-3|[/tex]
[tex]\\ \sf\longmapsto g(2)=|2-3|=|-1|=1[/tex]
[tex]\\ \sf\longmapsto g(-2)=|-2-3|=|-5|=5[/tex]
[tex]\\ \sf\longmapsto -g(2)=-1[/tex]
Odd function✓
#3
[tex]\\ \sf\longmapsto f(x)=\dfrac{x}{x^2-1}[/tex]
[tex]\\ \sf\longmapsto f(3)=\dfrac{3}{3^2-1}=\dfrac{3}{9-1}=\dfrac{3}{8}[/tex]
[tex]\\ \sf\longmapsto f(-3)=\dfrac{-3}{(-3)^2-1}=\dfrac{-3}{8}[/tex]
[tex]\\ \sf\longmapsto -f(3)=\dfrac{-3}{8}[/tex]
Odd function ✓
#4
[tex]\\ \sf\longmapsto g(x)=x+x^2[/tex]
[tex]\\ \sf\longmapsto g(1)=1+(1)^2=2[/tex]
[tex]\\ \sf\longmapsto g(-1)=-1+(-1)^2=0[/tex]
[tex]\\ \sf\longmapsto -g(1)=-2[/tex]
Neither✓