Product Rule and Trigonometric Derivates
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Hi Kevin!
I found two little bugs in this problem:
1) a typo after the line "For example..." d/dx cos(3x^2) = -3xsin(3x^2) should be d/dx cos(3x^2) = -6xsin(3x^2)
2) the second one is related to the checker: I have the same result as the checker is expecting in case of sin functions. But if the expression contains a cos function we differ by a -1 multiplier. I think you forgot to multiply the derivate of cos function by -1.
Excuse me for writing too much to you, I hope that this is not the reason you have been "offline" recently and you are well!
Hi Adam!
Apologies for the lack of responses recently - everything is well! Just some other priorities have been taking up most spare time recently, wrapping up some end-of-year projects at work and things like that. And don't feel as though you are writing too much or anything like that!!
I was able to take a few moments the other day to troubleshoot the "Blocked View" problem. The fort shouldn't be ending up inside the tree anymore :)
Reading your post here it does look like there is indeed an error with the example and the checker. I should have some time to fix that one tonight. Thank you again for your troubleshooting with these!!
Hi Kevin,
it seems it is not fixed completely yet. E.g. sign of expected answer for expression 0.909 * cos(0.091 * x) + 8.367 is still wrong.
Hi Adam!
Thanks for the patience. It looks like there was still one case where the value was being negated, but then
the result wasn't being stored! In PHP the line was bcmul($value, -1) when it should have been
$value = bcmul($value, -1) - oops!. I do think that all error are indeed fixed now though, thanks!
Hi Kevin,
almost done, I think there is still an error somewhere. E.g for the following example: f(x) = -1.577 * x * sin(0.772 * x) + 9.565
Derivate of f(x): f'(x) = -1.577(sin(0.772x) + x * cos(0.772 * x) * 0.772)
Value of f'(x) when x=12.351 should be f'(12.351) = 15.1188747453049
I hope I was able to help ot troubleshoot :)
Hi Adam,
Thanks for pointing this out! With such a clear example I was able to troubleshoot the issue with checker code pretty quickly :)
It should be all set now - thanks again for your continued patience with this one!
Super, it works! Thank you!