Plz help with this: -
\[\tan [i \log_e{\frac{a-ib}{a+ib}}]\]
Simplify: -
Answer is : - \[\frac{2ab}{a^2-b^2}.\]
It is a complex number problem.
@TuringTest @Zarkon @myininaya Plz help
you can write any complex number in the form: \[z=x+iy=r e^{i \theta}\]
you got \[a-ib/a+ib=(a-ib)(a+ib)/a^2+b^2\] if you multiply and divide by conjugate
\[\frac{a-ib}{a+ib}=\frac{(a-ib)(a-ib)}{(a+ib)(a-ib)}=\frac{a^2-b^2-2abi}{a^2+b^2}\]
k:) I will do it nw:)
and you gey doing the above product the expresion mukushla said
get*
\[\frac{a^2-b^2-2abi}{a^2+b^2}=\frac{a^2-b^2}{a^2+b^2}-\frac{2ab}{a^2+b^2}i \]
and for the last one \[r=\sqrt{(\frac{a^2-b^2}{a^2+b^2})^2+(\frac{-2ab}{a^2+b^2})^2}=1\]
and \[\theta=\tan ^{-1} (\frac{-2ab}{a^2-b^2})=-\tan ^{-1} (\frac{2ab}{a^2-b^2})\]
I gt this much: - \[\tan [\log_e{(\frac{re^{ -i \theta}}{re^{i \theta}})^i]}\]
if a+bi = re^i theta
put them in exponential form after you separate imaginary and real part, and it will be easier
\[ \ln(a + ib) = \ln(a^2 + b^2) + i \arctan \left (\frac b a \right ) --(1)\] \[ \ln(a - ib) = \ln(a^2 + b^2) - i \arctan \left (\frac b a \right ) -- (2)\] \[ (1) -(2) = 2i\arctan \left (\frac b a \right ) -- (3)\]
So i get \[\tan [\log_e {\frac{e^\theta}{e^{- \theta}}}]\]
from my way
can plz anyone do from my way?
oh ya i gt this \[\tan( 2 \theta)\]& \[\theta = \tan ^{-1}(\frac{b}{a}.)\]
now what?
sorry, it was (2) - (1) = \[ (2) -(1) = -2i\arctan \left (\frac b a \right ) -- (3)\] \[ (3) \times i = 2\arctan \left (\frac b a \right )\] \[ \tan \left( 2\arctan \left (\frac b a \right ) \right) = \frac{2ab}{a^2 - b^2}\]
@experimentX Plz plz will u explain my way further:)
first step: \[ \ln \left ( a - ib \over a + ib \right) = \ln( a - ib) - \ln(a + ib) \] now follow from what i posted first.
\[\tan(2\theta)=\frac{2tan \theta}{1-tan^2 \theta} \\ \theta=tan^{-1} \frac{b}{a} \\ so \ \ \frac{2tan \theta}{1-tan^2 \theta}=\frac{2b/a}{1-b^2/a^2}=\frac{2ab}{a^-b^2}\]
\[ \tan 2 \theta = \frac{2\tan\theta }{1 - \tan^2\theta }\]
Oh ya i gt it:) thanx:)
to alll:_)
I mean:)
yw
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