Identify function: First, identify the function to differentiate: f(x)=(57)sin2(2x).
Apply chain rule: Apply the chain rule for differentiation. Let u=sin(2x), then f(x)=57u2. The derivative of u2 is 2udxdu.
Differentiate u: Differentiate u=sin(2x). Using the chain rule again, dxdu=cos(2x)⋅ derivative of 2x, which is 2. So, dxdu=2cos(2x).
Substitute back: Substitute back to find f′(x). f′(x)=57⋅2⋅sin(2x)⋅2cos(2x). Simplify to get f′(x)=528sin(2x)cos(2x).
Use double-angle identity: Use the double-angle identity for sine, sin(2θ)=2sin(θ)cos(θ). Here, θ=2x, so sin(4x)=2sin(2x)cos(2x). Therefore, f′(x)=514sin(4x).