I find it much easier to enter equations in the Text mode (red bold text). In the past I found a UI setting that allowed me to stay in this mode, but now I can't remember where to find the option...so every time after I input a command, the next command is back in Math mode by default. How can I make it stay in Text entry mode all the time?

I frequently have a problem where evalf does not fully evaluate an expression.   First of all it stops at constant expressions.  For example,  "evalf(pi)" does not give me "3.14..." it just says "pi".

Also, it sometimes does not finish evaluating expressions.  For example,

 

Are there any ways to overcome these issues?

I don't understand what I'm doing wrong with the plot command...a screenshot shows best: