Given that y = (3x^4 + x)^5, find dy/dx using the chain rule.

Let u = 3x⁴ + x
du/dx = 12x³ + 1
y = u⁵
dy/du = 5u⁴
Using the chain rule, dy/dx = dy/du x du/dx
= 5u⁴ (12x³ + 1)
dy/dx = 5(3x⁴ + x)(12x³ +1)