Q. Given that y=3u5+2, find dud(2y3−2sinu) in terms of only u.Answer:
Express y in terms of u: First, we need to express y in terms of u, which is already given as y=3u5+2. We will use this to find the derivative of y with respect to u (dudy).
Calculate dy/du: Calculate the derivative of y with respect to u (dy/du). Since y=3u5+2, the derivative is dy/du=d/du(3u5+2)=15u4.
Find derivative with chain rule: Now, we need to find the derivative of the given expression 2y3−2sin(u) with respect to u. We will use the chain rule for the term 2y3 and the basic derivative rule for the term −2sin(u).
Apply chain rule to 2y3: Apply the chain rule to the term 2y3. 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. In this case, the outer function is f(y)=2y3 and the inner function is y(u)=3u5+2.
Calculate derivative of −2sin(u): The derivative of the outer function f(y)=2y3 with respect to y is f′(y)=6y2. We will then multiply this by the derivative of the inner function dudy, which we found to be 15u4.
Combine derivatives: The derivative of the term 2y3 with respect to u is therefore 6y2dudy=6y2⋅15u4. We substitute y=3u5+2 into this expression to get 6(3u5+2)2⋅15u4.
Simplify final expression: Now, calculate the derivative of the term −2sin(u) with respect to u. The derivative of −2sin(u) with respect to u is −2cos(u).
Simplify final expression: Now, calculate the derivative of the term −2sin(u) with respect to u. The derivative of −2sin(u) with respect to u is −2cos(u).Combine the derivatives of both terms to get the derivative of the entire expression with respect to u. This gives us dud(2y3−2sin(u))=6(3u5+2)2⋅15u4−2cos(u).
Simplify final expression: Now, calculate the derivative of the term −2sin(u) with respect to u. The derivative of −2sin(u) with respect to u is −2cos(u).Combine the derivatives of both terms to get the derivative of the entire expression with respect to u. This gives us dud(2y3−2sin(u))=6(3u5+2)2⋅15u4−2cos(u).Simplify the expression by distributing and combining like terms. The final derivative in terms of u is 90u4(3u5+2)2−2cos(u).
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