AREA UNDER CURVE (TRAPZ)

LET SAY MY DATA LIKE PICTURE ATTACHED. HOW CAN I CALCULATE THE AREA UNDER CURVE UNTIL BASELINE. FOR EXAMPLE:

y1=sin(x)
baseline=y2=3

how do i use trapz? trapz(x,y1) and ?

[Sasuka Teo]

Answer 1

[Matt J]

 trapz(x,y1) - trapz(x,y2)

or

trapz(x,y3)

where y3=sin(x)-3.

Answer 2

[Siranjeevi Gurumani]

x = 0:0.1:2*pi;
y1 = sin(x);
y2 = 0.5;%range of sinx between [-1,1]
z = y1 - y2;
z(z<0) = 0;
Area_above_threshold = trapz(x,z)