Répondre :
g(x)=xrac(x(4-x))
g'(x)=rac(4x-x²)+x*(4-2x)/(2rac(4x-x²))
=rac(4x-x²)+(2x-x²)/rac(4x-x²)
=(4x-x²+2x-x²)/rac(4x-x²)
=(-2x²+6x)/rac(4x-x²)
g'(x)=rac(4x-x²)+x*(4-2x)/(2rac(4x-x²))
=rac(4x-x²)+(2x-x²)/rac(4x-x²)
=(4x-x²+2x-x²)/rac(4x-x²)
=(-2x²+6x)/rac(4x-x²)