Question

dy Find if y =u³+ 2u and u=x² + 5.
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Answer 1

Answer:

6x^5 + 60x^3 +154x

Explanation:

Hope you asked $\frac{dy}{dx}$

Given that, y  = u^3 + 2u and u = x^2 + 5

This is solved using the parametric form

$\frac{dy}{dx}$ = $\frac{dy}{du}$*$\frac{du}{dx}$

dy/du = 3u^2 + 2

du/dx = 2x

Therefore, dy/dx = (3u^2 + 2)*2x = 6u^2 + 4x

Substitute for u,

dy/du = 6(x^2 +5)x + 4x = 6x^5 + 60x^3 +154x

Hope this helps!