Array index error help

Can anyone explain to me why I'm geeting an array indexing error for this script?

Array indices must be positive integers or logical values.

"Error in Finding_rp_test (line 32)

rn = (An(1-(En^2)))./(1+En*cos(thn));"

It's in the last line where I assign rn (Intending on running this for an array of 't' not just a single value).

An = 178942976.896420
En = 0.1781
t    = 1
Mn   = Nn*t;
EE0n = Mn;
DEEn = ((Mn-EE0n)+En*sin(EE0n))./(1-En*cos(EE0n));

    if En==0
        thn = Mn;
    else
        while DEEn>10^-12
            DEEn = (Mn-EE0n+(En*sin(EE0n)))./(1-(En*cos(EE0n)));
            EE0n = EE0n + DEEn;
            thn  = 2*atan((((1+En)./(1-En))^0.5)*tan(EE0n./2));
        end    
    end
    
    rn = (An(1-(En^2)))./(1+En*cos(thn));

Answer 1

[Image Analyst]

An is a scalar, not an array, so perhaps you meant:

rn = (An*(1-(En^2)))./(1+En*cos(thn));

[Scott Hunter]

Wow, massive facepalm. Been looking at it for days, all just a typo! Thank you!