how to solve 'Index exceeds the number of array elements (1)'?

In a function, the error in the title appears with Error in sol_rad (line 13) dec = -(dec0)*(pi/180)*cos(wI(I+9)); coming up after it. How do I get around this?

function [Qsun] = sol_rad(t,I,nc,lat)

% t = Time of day (seconds) % I = Time of year (days) % nc = Cloud cover % lat = Latitude

wt = (2*pi)/86400; % Units: s-1 wI = (2*pi)/365; % Units: yr-1 dec0 = deg2rad(23.45);

% 2.1 dec = -(dec0)*(pi/180)*cos(wI(I+9));

% 2.2 sinh = max(0,sin(lat)*sin(dec)+cos(lat)*cos(dec)*cos(wt(t+43200))); h = asin(sinh);

% 2.3 S = 1357 + 45*cos(wI*I);

% 2.4 m = 1/sin(h);

% 2.5 Cext = 0.128 - 0.0235*ln(m);

% 2.6 if h > 0 Insd = S*e^(-Cext*m)*sin(h)*(1-0.71*nc); else Insd = 0; end

% 2.7 Insg = 0.52*nc*Insd;

% 2.8 i = (pi/2)-h;

% 2.9 j = arcsin(0.75*sin(i));

% 2.10 r = 0.5*((sin(i-j)^2/(sin(i+j)^2))+((tan(i-j)^2)/(tan(i+j)^2))); if r < 0 r = r*-1; end

% 2. Qsun = Insd(1-r) + 0.97*Insg

Answer 1

[Star Strider]

You need an operator here (I chose ‘*’ for multiplication):

dec = -(dec0)*(pi/180)*cos(wI*(I+9));
                             ↑

[Dan Williams]

Cheers bro!

[Star Strider]

Cheers!