Q. Given that u=w3−4, find dwd(4u2+5cosw) in terms of only w.Answer:
Given function u: We are given the function u in terms of w:u=w3−4We need to find the derivative of the expression 4u2+5cos(w) with respect to w. To do this, we will use the chain rule for differentiation, which states that the derivative of a composite function is the derivative of the outer function times the derivative of the inner function.
Derivative of u: First, let's find the derivative of u with respect to w:dwdu=dwd(w3−4)Using the power rule, we get:dwdu=3w2
Derivative of 4u2: Now, let's differentiate the expression 4u2 with respect to u: dud(4u2)=8u
Chain rule application: Next, we apply the chain rule to find the derivative of 4u2 with respect to w: dwd(4u2)=dud(4u2)⋅dwduSubstitute the derivatives we found:dwd(4u2)=8u⋅3w2
Derivative of 5cos(w): Now, let's differentiate 5cos(w) with respect to w:dwd(5cos(w))=−5sin(w)
Combining derivatives: Combine the derivatives of 4u2 and 5cos(w) to find the total derivative with respect to w: dwd(4u2+5cos(w))=dwd(4u2)+dwd(5cos(w))Substitute the derivatives we found:dwd(4u2+5cos(w))=8u⋅3w2−5sin(w)
Expressing u in terms of w: Now, we need to express u in terms of w using the given u=w3−4:dwd(4u2+5cos(w))=8(w3−4)⋅3w2−5sin(w)
Simplifying the expression: Simplify the expression: dwd(4u2+5cos(w))=24w2(w3−4)−5sin(w)
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