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.

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

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