Posted by Shreya on .
for which of following functions is graphof y = f(x) identical to graph of y = f(x)?
A. f(x) = 2x
B. f(x) = 2x
C. f(x) = 2x^2
D. f(x) = 2x^2
i real not get this.

mathcalculus 
Damon,
has to be positive for all x
has to be an even function, same + or 
so
2 x^2 
mathcalculus 
Shreya,
ok can u explain to me again that i still not get it.

mathcalculus 
Steve,
f(x) is positive, but
2x can be negative
2x can be negative
x^2 is always positive, so
2x^2 is always negative.
The only choice which is always positive is 2x^2
so, 2x^2 = 2x^2