Need help with this:
tan(pi/2 + arctan(1/2))
Cheers!
Hello,
Here is my way but you can do the way you want...
$\displaystyle \tan(x)=\frac{\sin(x)}{\cos(x)}$
$\displaystyle \sin \left(\tfrac \pi 2+x\right)=\cos(x)$
$\displaystyle \cos \left(\tfrac \pi 2+x\right)=-\sin(x)$
(you can check it on a unit circle)
Therefore $\displaystyle \tan \left(\tfrac \pi 2+x\right)=\frac{\cos(x)}{-\sin(x)}=-\frac{1}{\tan(x)}$
So $\displaystyle \tan \left(\tfrac \pi 2+\arctan \left(\tfrac 12\right)\right)=-\frac{1}{\tan(\arctan \left(\tfrac 12\right))}=-\frac{1}{\tfrac 12}=\boxed{-2}$