Minor complains for the Android built-in calculator

I love to play with calculators. They are fun toys and relief you from mundane calculation routines.

Just about every phone comes with a calculator app. I have some minor complains with the default Android calculator.

I love the test case of dividing by 0. This is the only taboo function in the calculator world. 1 / 0 is... ∞ (infinity)?
Ah ha, once you get ∞, you can add stuff or subtract stuff from it... of course still infinity.

I beg to differ for this answer. Dividing by 0 is undefined, not infinity!

There is a Advanced Panel, with trigs and log function there. Ok, let me try other invalid operations like log of a negative number, it tells me "Error". Good.
Why can't "Error" be used in dividing by 0?

Technically, even log of a negative number is defined when you involve the complex numbers, but dividing by 0 is not.

Now, sin(30). Why is it not 1/2? Oh it is stuck in radian mode.

There are PLENTY of Android calculator apps out there, and I am not going to bother to build my own. I built a 4 function calculator and RPN calculator in Turbo Pascal in high school.