Standard lab part 1, G

[Oskar Kärrman]

The lab description instructs us to write a function differentiate which should find the derivate of an expression, but we're not instructed to implement negative numbers, and the derivate of cos x is -sin x. What to do?

[David Sands]

I don’t think it says that you should not implement negative numbers.  You should be able to parse negative numbers.

[Oskar Kärrman]

Okay, with negative numbers there's no problem.

This is the part of the description which confused me:

In other words, an expression consists of:

* Numbers; these can be (positive) integers as well as floating point numbers

[David Sands]

Ah - yes.  Thanks.  That is not helpful.  I have fixed the description.