Question

1)d/dx of cos4x/3-x^2(inculding quentient&chain rule)
2)sin^2x/1+cosx(same method)

Answer 1

#1

y = cos 4x/(3-x^2)

dy/dx = ( (3-x^2)(-4sin 4x) - cos 4x (-2x) )/(3-x^2)^2

try the second one, let me know what you got

Answer 2

you might be surprised at the answer to #2, unless you note that

sin^2/(1+cos) = (1-cos^2)/(1+cos) = 1-cos
no need for quotient rule or chain rule here.