Apply Chain Rule: Apply the chain rule to the function sin7(x). The chain rule states that the derivative of a composite function f(g(x)) is f′(g(x))g′(x). In this case, f(u)=u7 and g(x)=sin(x), so we need to find the derivatives f′(u) and g′(x).
Derivative of u7: Find the derivative of f(u)=u7 with respect to u. Using the power rule, (dud)(un)=nu(n−1), we get: (dud)(u7)=7u(7−1)=7u6.
Derivative of sin(x): Find the derivative of g(x)=sin(x) with respect to x.The derivative of sin(x) with respect to x is cos(x).dxd(sin(x))=cos(x).
Apply Chain Rule Again: Apply the chain rule using the derivatives from Step 2 and Step 3.The derivative of sin7(x) with respect to x is:dxd(sin7(x))=7(sin(x))6⋅cos(x).
Match Result: Match the result with the given options.The correct answer is (A)7sin6(x)cos(x), which matches our result from Step 4.
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