Sinx×cos²x+sin³x-sinx Sinx×cos²x+sin²x-sinx Aide moi svp

On sait que:
Sin^2 + cos^2=1
Alors:
Sinx*cos^2x + sin^3x-sinx
Sinx*cos^2 + sinx(sin^2-1)
Sinx(cos^2+sin^2-1)
Sinx(1-1) = Sinx

Sinx*cos^2+sin^2x+sinx
Sinx*cos^2+sinx(sinx+1)
Sinx(cos^2+sinx+1)
Jc plus continuer

Bonjour,

On sait que : cos²(x) + sin²(x) = 1 donc cos²(x) = 1 - sin²(x)

    sin(x).cos²(x) + sin^3(x) - sin(x)
= sin(x).cos²(x) + sin(x)(sin²(x) - 1) 
= sin(x)(1 - sin²(x)) + sin(x)(sin²(x) - 1)
= sin(x) - sin^3(c) + sin^3(x) - sin(x) 
= 0

Bonne chance