Answer:
d y dx=0 
Step-by-step explanation:
From the given
y=sin2x+cos2x
 
The right side of the equation is 
=1
y=1
d y d x=d d x(1)=0 
or we can do it this way.
y = sin2x+cos2x
 
d y d x=2
⋅(sinx)2−1
⋅
d d x(sinx)+2
(cosx)2−1 d d x(cosx)
d y d x=2⋅
sinx⋅cosx+2⋅cosx⋅(−sinx)
dydx=2⋅sinx⋅cosx−2⋅sinx⋅cosx
dydx=0
God bless....I hope the explanation is useful.