Maths Evaluate Question

Evaluate
d/dx x^(n) + 5x

x=1 below d/dx

What do you mean by the second part?

This is the question

Which part are you having trouble with? It looks straightforward.

Well, haven’t really done any evaluation like this at A-Level.
My answer was n^(n-1) + 5 but apparently this is wrong.
The question after is simple as well but I can’t do it either. It was sin(t) with the text below saying t = pi.
Apparently the answer can’t be cos(pi) as it must be an integer or decimal so I put zero as well but apparently that was wrong too. Maybe I’m just answering them wrong?

Notation means: "find d/dx for the expression, the final answer is what you get when you substitute x=1 into that expression".

How do you differentiate x^2, x^3, ..., x^n? Spot the pattern. Then 1^(n-1) =...
You must have covered this.

Notation means: "find d/dx for the expression, the final answer is what you get when you substitute x=1 into that expression".

1^(n-1) = ...
So the answer is ...

Where have you only got 1 from? Surely it’s n^(n-1). If it’s 1 then overall obviously it equals 1 + 5 = 6 but that’s not correct...

What is the derivative of x^3?
Where is the x term in your expression n^(n-1)? Is this before or after you sub x=1

Oh I get you now man. I’m being stupid. Anything multiplied by 1 is 1. So 1^n-1 is 1... but how come the answer isn’t 6 then? I’ve tried that before.

You are rusty :-).
What is the derivative before you sub x=1?

nx^(n-1) + 5

Ok so sub x=1 and remember there are two operations in the first term: multiplication and power.

You end up with the indice not having an effect first, since 1 to the power of anything is 1. Then you just have nx + 5, which isn’t the correct answer btw

Why x in that expression? You've replaced it with 1?