Question

Aflati zeroul functiei f : R ⇒R , dacă
a) f (x) =2x + 1
b) f (x)= 3- 5x
c) f (x) = radical 10x
d) (x) = $\frac{1}{2}$x - 7,2

Answer 1

a)f(x)=2x+1
2x+1=0
2x=-1
x=-1/2
f(0)=2·0+1=1
f(-1/2)=0

b)f(x)=3-5x
3-5x=0
-5x=-3   inmultim -1
x=3/5
x=0,6
f(0)=3
f(0,6)=0

c) f(x)=√10x
√10x=0
x=0
f(0)=0

d)f(x)=x/2-7,2
x/2-7,2=0
x/2=7,2
x/2=72/10
10x=72·2
x=72·2/10
x=72/5
x=14,4
f(0)=-7,2
f(14,4)=0