Hi I'm a bit confused about some mathematical notation(adsbygoogle = window.adsbygoogle || []).push({});

If i write

f(x)=(2x^2 + 10)^4

And i define

u= 2x^2 +10

u^4 = f(x)

Would it then be correct to write

f(u)= u^4

Or would i get

f(u)= 2(u)^2 +10 = (2(2x^2 +10)+10)^2

Should i define u^4 = f(x) first? Would it then be correct?

My book writes that if u is a function of x then then you can put u into x and get the following.

∫f(u)du = F(g(x))

So I want to make sure I'm assuming correctly.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Writing correct mathematics -- functions within functions...

**Physics Forums | Science Articles, Homework Help, Discussion**