Let f(x) be a polynomial of the second degree. If f(1)=f(-1) and a1:a2:a3 are in AP then f'(a1):f'(a2):f'(a3) are in
AP
GP
HP
None of these
Explanation for the correct option:
let f(x)=ax2+bx+c
f(1)=a+b+cf(-1)=a-b+c
a+b+c=a-b+c⇒b=0
f(x)=ax2+c
f'(x)=2ax
f'a1=2aa1f'a2=2aa2f'a3=2aa3
They are in AP since a1,a2,a3are in AP
Hence, option(A) is the correct answer