Calculus Derivatives help?

What in the world is 3 * tan^6(pi/12)^2? Is it 3 * tan((pi/12)^2)^6? Either way, without a variable present, you could just call it a constant C

5x^3 - 3x^5 - C

That's easy enough to derive

15x^2 - 15x^4

x^2 * sqrt(x^3 + 1) / (x - 2)

u = x^2 * sqrt(x^3 + 1)

u^2 = x^4 * (x^3 + 1)

u^2 = x^7 + x^4

2u * du = 7x^6 * dx + 4x^3 * dx

du/dx = (7x^6 + 4x^3) / (2u)

u' = x^3 * (7x^3 + 4) / (2 * x^2 * sqrt(x^3 + 1))

u' = x * (7x^3 + 4) / (2 * sqrt(x^3 + 1))

v = x - 2

v' = 1

d(u/v) = (v * u' - u * v') / v^2

((x - 2) * x * (7x^3 + 4) / (2 * sqrt(x^3 + 1)) - x^2 * sqrt(x^3 + 1) * 1) / (x - 2)^2 =>

(1/sqrt(x^3 + 1)) * ((x - 2) * x * (7x^3 + 4) * sqrt(x^3 + 1) - x^2 * (x^3 + 1)) / (x - 2)^2 =>

(x * (x - 2) * (7x^3 + 4) * sqrt(x^3 + 1) / 2 - x^2 * (x^3 + 1)) / ((x - 2)^2 * sqrt(x^3 + 1)) =>

(x * (x - 2) * (7x^3 + 4) * sqrt(x^3 + 1) - 2 * x^2 * (x^3 + 1)) / (2 * (x - 2)^2 * sqrt(x^3 + 1))

What's wrong with a derivative calculator?

That question is too hard for people on here you need to go ask a university professor