Can someone explain it to me step by step?
Add parenthesis to show clearly what the equation is and what the exponents are applied to.
You can apply the chain rule repeatedly to (sin((x+1)2))3 = f(g(h(x))), where f(g) = g3, g(h)=sin(h), and h(x)=(x+1)2.
The overall equation is
df/dx = df/dg|g ⋅ dg/dh|h ⋅ dh/dx
df/dg = 3g2; dg/dh = cos(h); dh/dx = 2(x+1).
Substituting in gives df/dx = 3(sin((x+1)2))2 ⋅ cos((x+1)2) ⋅ 2(x+1)
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