Question: Evaluate equation with degrees

Good morning, I'm trying to evaluate this equation when x = 10 degrees so that it gives me a value something like this -0.1671897 etc. but I can't find a way to do it. I've tried to do it like this:

with(Degrees);
evalf(eq, tand(10));

with(Units:-Simple);
evalf(eq, tan(10*Unit(degree) ;

But it gives me an error. In other words, how do I evaluate the equation at 10 degrees.

 

Please Wait...