f:D>R
D= [0;π] nu ne-ai specificat inchis sau descchis
f(x) =sinx+x
f'(x)=cosx+1
nu ne-ai specificat nici punctul in carese cere ecuatia tangentei
sa zicem ca ar fi π/2
y-f(π/2) =f'(π/2) * (x-π/2)
y-sin π/2+π/2= (cosπ/2 +1)(x-π/2)
y-1+π/2=1(x-π/2)
y-1+π/2=x-π/2
y=x+1-π/2-π/2
y=x+1-π
x/(x²+1): {-1;0;1}->R
f(x) definita pe multime finita, discreta; f(x)nu estederivabila
