Q. Given that y=u3+3, find dud(3y2+4sinu) in terms of only u.Answer:
Find Derivative of y: First, we need to find the derivative of y with respect to u, since y is a function of u. The given function is y=u3+3.Using the power rule for differentiation, the derivative of u3 with respect to u is 3u2, and the derivative of a constant is 0.So, y0.
Derivative of 3y2: Next, we need to find the derivative of 3y2 with respect to y. Using the power rule again, the derivative of y2 with respect to y is 2y. So, dyd(3y2)=3×2y=6y.
Apply Chain Rule: Now, we apply the chain rule to find the derivative of 3y2 with respect to u. The chain rule states that dud(f(g(u)))=f′(g(u))⋅g′(u). Here, f(y)=3y2 and g(u)=y, so we have dud(3y2)=dyd(3y2)⋅dudy=6y⋅3u2.
Substitute y into Expression: We substitute y=u3+3 into the expression we found in the previous step to express it in terms of u. So, dud(3y2)=6(u3+3)⋅3u2.
Simplify Expression: Now, we simplify the expression we found in the previous step.dud(3y2)=6(u3+3)×3u2=18u2(u3+3).
Derivative of 4sinu: Next, we find the derivative of 4sinu with respect to u. The derivative of sinu with respect to u is cosu. So, dud(4sinu)=4cosu.
Add Derivatives: Finally, we add the derivatives we found for 3y2 and 4sinu to find the derivative of the entire expression 3y2+4sinu with respect to u.dud(3y2+4sinu)=dud(3y2)+dud(4sinu)=18u2(u3+3)+4cosu.
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