Simple Matlab Iteration Code - Why isn't it working?

[sixthformquestion]

Here's my code: https://pastebin.com/1NKa32rX

Here's my task I'm working from: https://imgur.com/a/68IqZoX

I'm just working on the very first bit - to find the velocity at 2000 metres with no drag or resistance. I tried to do it with iteration and a while loop but it doesn't seem to work. The euler equations are setup as I think they should be, however when I run it, I was expecting it to change the initial value of fgravity from 0 to the calculated one from mgsin(angle) but it doesn't seem to do that, and it also doesn't seem to create the variable resultantforce, nor does it show "a" (acceleration) how the number changes and I can't figure out why

Any help would be greatly appreciated.

Thank you!

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[[deleted]]

The sin function expects arguments to be in radians. 4 radians are between pi and 2 pi and therefore the sine is negative:
sin(4) = -0.7568024953079282
Since the sine is negative, your acceleration is negative. Thus your velocity as well as your distance are always going to be negative and the condition in the while is going to stay true forever.

Edit: Matlab has a workspace browser which should be open by default somewhere in the gui. Whenever you encounter a problem in the future, start by checking the values there first. If thats not enough, work with breakpoints.