Show that the function is a. strictly increasing on ]0, ∞[ b. strictly decreasing on] − ∞, 0[

Question

Philoid · Accepted Answer

For x>0

Modulus will open with + sign

f(x)=+x

⇒ f’(x)=+1 which is <0

for x<0

Modulus will open with -ve sign

f(x)=-x => f’(x)=-1 which is >0

hence f(x) is increasing in x>0 and decreasing in x<0