# Why does the google calculator give $\tan 90^{\circ} = 1.6331779e^{+16}$?

I typed in $$\tan 90^{\circ}$$ in Google and it gave $$1.6331779\mathrm{E}16$$. How did it come to this answer? Limits? Some magic?

The closest IEEE-754 double value to $\pi/2$ is $1.5707963267948965579989817342720925807952880859375$. The cosine of that, on standard x86_64 hardware evaluates to $6.123233995736766 \times 10^{-17}$. The reciprocal of that is $1.633123935319537 \times 10^{16}$.