Cho các hàm số :
f1(x) = \(3x^2\); f2(x) = -5x; f3(x) = \(\frac{3}{x}\); f(4) = \(x^4\) + \(x^2\); f5(x) = \(x^4\) + \(x^2\).
a) Tính f1(\(\frac{1}{3}\)); f2(\(\frac{1}{5}\)); f3(3); f4(-1); f5(1)
b) Tính A = f1(0) + f2(5) + f3(3) + f4(-2) + f5(2)
c) So sánh f1(x) và f1(-x); f2(x) và -f2(-x)
d) Tìm x, biết: f5(x) =0: f5(x) =-1
a: \(f_1\left(\dfrac{1}{3}\right)=3\cdot\dfrac{1}{9}=\dfrac{1}{3}\)
\(f2\left(\dfrac{1}{5}\right)=-5\cdot\dfrac{1}{5}=-1\)
\(f3\left(3\right)=\dfrac{3}{3}=1\)
\(f4\left(-1\right)=1+1=2\)
f5(1)=1+1=2
b: \(A=3\cdot0^2+\left(-5\right)\cdot5+\dfrac{3}{3}+\left(-2\right)^4+\left(-2\right)^2+2^4+2^2\)
=-25+1+16+4+16+4
=-24+40
=16