cho ham so y=f(x)=x+x2+x3+.........+x2016
a) tinh f(1/3)
b)tinh f(-5)
cho ham so y=f(x) thoa man dieu kien f(x1+x2)=f(x1)+f(x2) va f(x)-xf(-x)=x+1 voi moi x thuoc R
A CMR M(0,1)thuoc do thi ham so
B Tinh f(2019)
cho ham so y=f(x)=4x^2-5.a,tinh f(3).f(-1/2) b,tim x de f(x)=-1
\(a,\)
\(y=f\left(3\right)=4.3^2-5=31\)
\(y=f\left(-\frac{1}{2}\right)=4.\left(-\frac{1}{2}\right)^2-5=-4\)
\(b,\)
\(y=f\left(x\right)=4x^2-5\)
\(\Leftrightarrow4.x^2-5=-1\)
\(\Leftrightarrow4.x^2=4\)
\(\Leftrightarrow x^2=1\)
\(\Leftrightarrow x=1\)
y=ƒ (3)=4.3²−5=31
y=ƒ (−1/2 )=4.(−1/2 )2−5=−4
b,
y=ƒ (x)=4x2−5
⇔4.x2−5=−1
⇔4.x²=4
⇔x²=1
⇔x=1
chúc bn học tốt
Cho ham so f(x) thoa man : f(x1*x2)=f(x1)*f(x2) va f(2)=5 . tinh f(8)
cho ham so : y=f(x)=1/2x
a,tinh f(-1),f(3),f(6)
b,ve do thi ham so da cho
cho ham so y=f<x>=3x{1}
A,ve do thi ham so {1}
B,tinh f(0);f(-1/3)
Cho ham so y=f(x) =3x - 8
a)Tinh f(3) ; f(-2)
b)Tinh x khi biet gia tri tuong ung y la 1
Lời giải:
a)
\(f(3)=3.3-8=1\)
\(f(-2)=3(-2)-8=-14\)
b)
\(y=f(x)=3x-8=1\)
\(\Leftrightarrow 3x=9\Leftrightarrow x=3\)
cho ham so y=\(\dfrac{3}{2}\)x =f(x)
a)tinh f(-1);f(2);f(-4)
b)ve do thi ham so tren
f(-1) = \(\dfrac{3}{2}.-1=-\dfrac{3}{2}\)
f(-2) = \(\dfrac{3}{2}.2=3\)
f(-4) = \(\dfrac{3}{2}.-4=-6\)
ch ham so y=f(x)=|x-1|+2
a,tinh f(-2); f(1/2)
b,tim x sao cho f(x)=3
a, Ta có: f(-2) = |-2 - 1| + 2 = |-3| + 2 = 5
f(1/2) = |1/2 - 1| + 2 = |-0,5| + 2 =2,5
b, Ta có: f(x) = 3 =>|x - 1| + 2 = 3 => |x - 1| = 3 - 2 => |x - 1| = 1
=> x - 1 = 1 hoặc x - 1 = -1
=> x = 2 hoặc x = 0
cho ham so y=f(x)=-2x+3 .Tinh f(-2);f(-1);f(0);f(-1/2);f(1/2)
f(-2)=(-2)*(-2)+3=4+3=7
f(-1)=(-2)*(-1)+3=2+3=5
f(0)=-2*0+3=0+3=3
f(-1/2)=-2*(-1/2)+3=1+3=4
f(1/2)=-2*(1/2)+3=-1+3=2
Vậy f(-2)=7; f(-1)=5; f(0)=3; f(-1/2)=4; f(1/2)=2