Q. Given that u=4v2+1, find dvd(5v5−4sinu) in terms of only v.Answer:
Find Derivative with Chain Rule: We need to find the derivative of the function with respect to v. We will use the chain rule for the term involving u, since u is a function of v. The chain rule states that the derivative of a composite function is the derivative of the outer function evaluated at the inner function times the derivative of the inner function.
Differentiate 5v5: First, let's differentiate the term 5v5 with respect to v. The power rule for derivatives tells us that dvd(vn)=n⋅v(n−1), so the derivative of 5v5 with respect to v is 5⋅5v4=25v4.
Differentiate −4sin(u): Now, let's differentiate the term −4sin(u) with respect to v. Since u is a function of v, we need to use the chain rule. The derivative of −4sin(u) with respect to u is −4cos(u), and we need to multiply this by the derivative of u with respect to v, which is −4sin(u)0.
Apply Chain Rule for u: The derivative of u with respect to v is dvd(4v2+1)=8v, because the derivative of a constant is 0 and the derivative of 4v2 is 8v using the power rule.
Combine Derivatives: Now, we multiply the derivative of −4sin(u) with respect to u by the derivative of u with respect to v to get the full derivative of −4sin(u) with respect to v. This gives us −4cos(u)×8v=−32vcos(u).
Express in Terms of v: Finally, we combine the derivatives of both terms to get the full derivative of the function with respect to v. The derivative of 5v5−4sin(u) with respect to v is 25v4−32vcos(u).
Express in Terms of v: Finally, we combine the derivatives of both terms to get the full derivative of the function with respect to v. The derivative of 5v5−4sin(u) with respect to v is 25v4−32vcos(u).We need to express the derivative in terms of v only, so we substitute u=4v2+1 into the cosine term. This gives us −32vcos(4v2+1).
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