Q. Given that x=u2+2, find dud(2x3−3sinu) in terms of only u.Answer:
Express x in terms of u: First, we need to express x in terms of u, which is already given as x=u2+2. We will use this to find the derivative of x with respect to u.
Calculate derivative of x: Calculate the derivative of x with respect to u, which is dudx.dudx=dud(u2+2)dudx=2u+0dudx=2u
Apply chain rule: Now, we need to find the derivative of the expression 2x3−3sinu with respect to x and then with respect to u. We will use the chain rule for this, which states that dxd(f(g(x)))=f′(g(x))⋅g′(x).
Find derivative of 2x3: First, find the derivative of 2x3 with respect to x.dxd(2x3)=6x2
Find derivative of −3sinu: Next, find the derivative of −3sinu with respect to u.dud(−3sinu)=−3cosu
Apply chain rule to find derivative of 2x3: Now, apply the chain rule to find the derivative of 2x3 with respect to u. dud(2x3)=dxd(2x3)⋅dudxdud(2x3)=6x2⋅2u
Substitute x into derivative: Substitute x=u2+2 into the derivative of 2x3 with respect to u. dud(2x3)=6(u2+2)2⋅2u
Simplify the expression: Simplify the expression. dud(2x3)=12u(u2+2)2
Combine derivatives: Combine the derivatives of 2x3 and −3sinu with respect to u to get the final derivative of the expression 2x3−3sinu with respect to u. dud(2x3−3sinu)=12u(u2+2)2−3cosu
More problems from Evaluate rational expressions II