#is this an identity I’m not aware of with arctan?
48 messages · Page 1 of 1 (latest)
It’s the last step I don’t get
If it was log instead of tan-1 that would make sense to me cos u can bring the power to the front but I didn’t know u could do that with tan-1
New discovery club
I also got to know this now
On the internet
Fresh discovery for me too because of you
Is there a nice explanation for why that’s true
Wait
Cos this doesn’t work and I don’t see how it’s just off by a constant cos that is not the same graph
Hmm, I sure did see someone do it like this on the internet
Idk why
But see, I also do not have a correct explanation for this
Ah I see
Still, u can treat it like a property
Well I’m not convinced it will hold for all powers
And as the Desmos thing shows it doesn’t really seem true even with the ^-1
Maybe it does not work for cos inverse
So it’s a bit confusing
Cause cos returns positive value
For negative argument
We do need some advanced mathematicians for this problem
Yeah
Idk how to get advanced mathematicians to come here though 😂
It’s a huge server it’s hard to get noticed lol
Does that come from the fact that tan-1(x) + tan-1(1/x) = pi/2 ?
or -pi/2 but a constant anyway
@lone star it's not a trigonometric identity it is just re-substituting $u=\mathrm{csec}, x$ in $\tan^{-1} u = \tan^{-1}(\mathrm{csec},x) $
or do you ask how one got $\int\frac{1}{1+u^2}\ \mathrm{d}u = \tan^{-1}u$ ?
(if you ask the latter, try the substitution $u=\tan v$ and use the identity $1 + \tan^2 = 1/\cos^2$ that can easily obtained from $\cos^2 + \sin^2 = 1$ when dividing by $\cos^2$)
Landau08
Ohhhh that’ll be it!
Thanks but it’s okay I understand that I was confused about getting from the -tan^-1(cscx) to the tan^-1(sinx)
Because I put some numbers in and it was off by 1.5ish each time
So why is this true
Yeah
Found a nice explanation for why
sorry, I first misunderstood the question,; above geometric proof is nice
No worries :)
You can simply derive and prove the derivative is 0, that is enough for your initial problem, you don't care about the value of the constant
.solved