MATLAB: How to plot sin(x) for sin(x)>0, and 0 for sin(x)<=0

plot

Hello. I tried to use if statements but nothing worked.. Any piece of advice of how I should approach it? Thank you

Best Answer

syms y(x)
y=piecewise(sin(x)>0,sin(x),sin(x)<=0,0)
fplot(y,[-3*pi 3*pi])

Related Solutions

MATLAB: Sin(x)^2

Use the rewrite function:

syms x 
ys = sin(x)^2;
ye = rewrite(ys, 'exp')
yc = rewrite(expand(ye), 'cos')

p[roducing:

yc =
1/2 - cos(2*x)/2

MATLAB: Return any angle to (0 to 2pi) range

The short answer:

mod(x,2*pi)

The long answer for this particular mod operation, is that if you want to get the same answer for trig calculations for large inputs that MATLAB does, you need to do the mod differently:

atan2(sin(x),cos(x)); % effectively mod(x,2*pi)

E.g.,

>> x = 10
x =
    10
>> y = mod(x,2*pi)
y =
   3.716814692820414
>> sin(x)
ans =
  -0.544021110889370
>> sin(y)
ans =
  -0.544021110889370
>> x = 1e25
x =
     1.000000000000000e+25
>> y = mod(x,2*pi)
y =
     0
>> sin(x)
ans =
  -0.305257800135130
>> sin(y)
ans =
     0
>> z = atan2(sin(x),cos(x))
z =
  -0.310209139287907
>> sin(z)
ans =
  -0.305257800135130

Using the atan2( ) approach to doing the mod(x,2*pi) operation results in effectively the same angle that MATLAB uses for the trig operations.

Best Answer

Related Solutions

MATLAB: Sin(x)^2

MATLAB: Return any angle to (0 to 2pi) range

Related Question