Matlab says that the 'e' is undefined

Hi,

I trying to get an integral of a simple function F(x) = 3*x.^2 + e.^(2*x) and matlab won't let me enter the equation, so I am stuck with figuring out how to enter in the function F(x) into the system.

The question I am struggling on is, "compute the integral of the function F(x) using symbolic manipulation functionality", and I have no clue where to start on..

Please help me start off! Much appreciated if you guys could provide me with some commands as well.

Thank you!

Answer 1

[Guillaume]

In matlab, and many languages, the exponential function is exp, not e.

F(x) = 3*x.^2 + exp(2*x)

[Sarah Park]

Hi! Thank you for your answer, I have tried that already and Matlab says this:

"Subscript indices must either be real positive integers or logicals"

[Stephen23]

@Sarah Park: most likely you defined a variable named exp. Clear that variable.

[Sarah Park]

@stephen Cobeldick: Thank you for your answer! I just cleared everything in my workspace and entered the original x values

    x1=cos(pi/6);
    x2=cos(3*pi/6);
    x3=cos(5*pi/6);

but now it says: "undefined function or variable 'x'". I don't know what to do..

[Stephen23]

@Sarah Park: you show that you defined three variables named x1, x2, and x3, but apparently you do not define any variable named x.

"I don't know what to do.."

You need to define a variable before you can use in in any calculation or operation.

Answer 2

[Torsten]

See the examples under

https://de.mathworks.com/help/symbolic/int.html

Best wishes

Torsten.

[Sarah Park]

@Torsten: Thank you! I will look into it now :)