MATLAB: Can anyone explain the error shown

error

PolarAngle2 = [0:(1/180*pi):pi];
y = sin(PolarAngle2);
y = y';
SecondNormalizedIntensity = zeros(size(NormalizedIntensity));
for i = 1 : 1: 181
polarfun = @(PolarAngle2) 1./SecondNormalizedIntensity(i);
SecondNormalizedIntensity(i) = NormalizedIntensity(i) * y(i);
RadiantIntensity = zeros(size(SecondNormalizedIntensity));
RadiantIntensity = RadiantIntensity';
first = integral(polarfun,0,pi);
end

Best Answer

polarfun = @(PolarAngle) (1/SecondNormalizedIntensity);
defines polarfun as a single function handle.
RadiantIntensity(i) = integral(polarfun{i},-pi/2,pi/2);
refers to polarfun as if it were a cell array of function handles. The {i} part should not be there.