Répondre :
sinx/sin³(x) + Cosx/Cos³(x)
=1/cos²(x)+1/sin²(x)
=(cos²(x)+sin²(x))/(sin²(x)cos²(x)*2)
=2/(4*sin²(x)cos²(x))
=2/(sin(2x))²
svp aidez moi: sinX/sin3X + CosX/Cos3X= 2 demontrez cette egaliter, svp aider moi merci :)
sinx/sin³(x) + Cosx/Cos³(x)
=1/cos²(x)+1/sin²(x)
=(cos²(x)+sin²(x))/(sin²(x)cos²(x)*2)
=2/(4*sin²(x)cos²(x))
=2/(sin(2x))²