Error using 'pi' too many input errors with my equation

%Defining given varibles
t = 0 :.1 :3;
f1 = 130;
f2 = 120;
y1 = cosd(2*pi*f1*t);
y2 = cosd(2*pi*f2*t);



%% Section 2: Processing

%equation given
y = 2 * cos(2*pi(f1+f2/2)*t) * cos(2*pi(f1-f2/2)*t);


%% Section 3: Result Output
plot(y)
title('Alternating Loud and Quiet Sounds')
xlabel('Time(s)')
ylabel('Amplitutde')

[Serena Simpson]

The problem is with my 'y' equation

Answer 1

[Steven Lord]

You're missing * operators after the two calls to pi on the line where you define y, just like you did on the lines where you defined y1 and y2.

[Serena Simpson]

Oh. I see now. Thank you so much!!