Applications de la dérivation, cours, terminale STG - MathsFG

f I
•f I x I f0(x)≥0
•f I x I f0(x)≤0
•f I x I f0(x)=0
f[−3; 5]
x
f(x)& % &
f0
x
f0(x)
•x I f0(x)≥0f0(x)>0
f
I
•x I f 0(x)≤0f0(x)<0
f
I
•x I f0(x) = 0 f I
f[−3; 5]
x
f0x)

f
x
f(x)% & %
•fRf(x) = 4x3+ 5 fR
x f0(x) = 12x2x f0(x)>0f
R
•f f(x) = 4
2x+3 x[3; +∞[
f0(x) = −8
(2x+3)2
x[3; +∞[ (2x+ 3)2f0(x)<0f
[3; +∞[
•f]− ∞; +∞[f(x) = 3x2+ 7x f R
x f0(x)=6x+ 7
f0(x)≥0 6x+ 7 ≥0x≥−7
6
x−∞ −7
6+∞
f0(x)
f(x)& %
•fR∗f(x) = x+1
x
x6= 0
f0(x)=1−1
x2
=x2−1
x2
=(x−1)(x+ 1)
x2
x−∞ +∞
f0(x)k
k
f(x)% & k & %

f I x0I
•f(x0)f
J I
x0x J f(x)≤f(x0)f(x)≥f(x0)
•
f I
]a;b[
•f x0∈I x0
f0(x0)=0
•f0x0f x0
x x0
f(x)& %
f(x0)
x x0
f(x0)
f(x)% &