solve using first principle of differenciation

Question

1)y=sin{square root(x)}

Answer 1

start with the sum-to-product formula:

sin(√(x+h))-sin(√x)
= 2cos((√(x+h)+√x))/2)sin((√(x+h)-√x)/2)

or, try substituting u = √x

sin(√x) = √x sin(√x) / √x = u * sin(u)/u

and you know that lim sin(u)/u = 1