How to find the root mean square voltage of a Sine wave?

Question

I'm giving a code in matlab and have to answer some questions, I'm having some doubts on some of the questions I've done.

Original code:

%Paremeter setting
A = 1; %Amplitude
f = 1; %frequency
P = 0; %Phase
time = 1.5; %time duration
N = 1000; %Sampling number
t = 0:time/(N-1):time;
%Generate sin wave
s = A*sin(2*pift+P);
%Draw figure
plot(t,s)
grid on
xlabel('Time')
ylabel('Amplitude')

Questions:

1. Run the code and plot the figure; what is the period of the output signal?
2. Change the A = 0.5, then run the code; what is the root mean square voltage of the signal?
3. Change the f = 2, then run the code; what is the period of the output signal?
4. Change the P=pi/4, then run the code; what is the value of the single at time = 0?

My answers:

1. one second

2. This is what's confusing me: The peak is o.707, do I divide this by 2 or $\sqrt2$?

3. 0.5 seconds

4. 0.707

I'm having problems with question 2, but are the other answers correct?

Answer 1

For a sine wave (assumed symmetric around zero) the rms level is $\frac {\sqrt 2}2$ of the peak level. This is because the average value of $\sin^2$ is $\frac 12$, which you can show by integration.