applying while loop for solving simultaneous equations

I am trying to include a condition that 'tan(alphac)<(1/lam)' in the following code. Here, ''alphac'' is dependent of ''x''. and the value of x is determined at last. I want to write a code such that the value of x is determined by applying the condition.

code:

dbstop if error

clear all

clc

format longEng

syms x y lam

a=[4;0.55];

% The Newton-Raphson iterations starts here

LAM=linspace(0,10,11);

h=4;

q=20;

gma=18.4; nq=2*q/(gma*(h+x));

delta=26;

phi=39;

A=lam*nq/(1+nq);

kv=0;

kh=0;

da1=delta*(pi/180); da2=-delta*(pi/180); pha1=phi*(pi/180); pha2=phi*(pi/180);

dp1=delta*(pi/180); dp2=delta*(pi/180); php1=phi*(pi/180); php2=phi*(pi/180);

psi=atan(kh/(1-kv));

m=pha1+da1;

b=pha1-psi;

c=psi+da1;

alphac=atan((sin(m)*sin(b)+(sin(m)^2*sin(b)^2+sin(m)*cos(m)*sin(b)*cos(b)+A*cos(c)*cos(m)*sin(b))^0.5)/(A*cos(c)+sin(m)*cos(b)))

kg=(tan(alphac-pha1)+(kh/(1-kv)))/(tan(alphac)*(cos(da1)+sin(da1)*tan(alphac-pha1)));

r=1-lam*tan(alphac);

kq=r*kg;

A2=0;

alphac2=atan((sin(m)*sin(b)+(sin(m)^2*sin(b)^2+sin(m)*cos(m)*sin(b)*cos(b)+A2*cos(c)*cos(m)*sin(b))^0.5)/(A2*cos(c)+sin(m)*cos(b)))

kg2=(tan(alphac2-pha1)+(kh/(1-kv)))/(tan(alphac2)*(cos(da1)+sin(da1)*tan(alphac2-pha1)));

pg=0.5*gma*(1-kv)*kg2*(h+x)^2;

A=1;

alphac1=atan((sin(m)*sin(b)+(sin(m)^2*sin(b)^2+sin(m)*cos(m)*sin(b)*cos(b)+A*cos(c)*cos(m)*sin(b))^0.5)/(A*cos(c)+sin(m)*cos(b)))

kg1=(tan(alphac1-pha1)+(kh/(1-kv)))/(tan(alphac1)*(cos(da1)+sin(da1)*tan(alphac1-pha1)));

r1=1-lam*tan(alphac1);

kq1=r1*kg1;

pq=(1-kv)*(q*kq*(h+x)+0.5*q*(kq1-kq)*(h+x));

va2=asin(sin(da2)/sin(pha2))-asin(sin(psi)/sin(pha2))-da2-psi;

ka2=(1/cos(psi))*(cos(da2)*((cos(da2)-sqrt(sin(pha2)^2-sin(da2)^2)))/(cos(psi)+sqrt(sin(pha2)^2-sin(psi)^2)))*exp(-va2*tan(pha2));

vp1=asin(sin(dp1)/sin(php1))+asin(-sin(psi)/sin(php1))+dp1+psi;

kp1=(1/cos(psi))*(cos(dp1)*((cos(dp1)+sqrt(sin(php1)^2-sin(dp1)^2)))/(cos(psi)-sqrt(sin(php1)^2-sin(psi)^2)))*exp(vp1*tan(php1));

vp2=asin(sin(dp2)/sin(php2))+asin(-sin(psi)/sin(php2))+dp2+psi;

kp2=(1/cos(psi))*(cos(dp2)*((cos(dp2)+sqrt(sin(php2)^2-sin(dp2)^2)))/(cos(psi)-sqrt(sin(php2)^2-sin(psi)^2)))*exp(vp2*tan(php2));

sinda1=sin(da1); sindp1=sin(dp1); sinda2=-sin(da2); sindp2=sin(dp2);

cosda1=cos(da1); cosdp1=cos(dp1); cosda2=cos(da2); cosdp2=cos(dp2);

pp1=kp1*gma*0.5*(x^2);

pa2=ka2*gma*(x*y+0.5*(y^2)); pp2=kp2*gma*(y*(h+x)+(0.5*(y^2)));

zp1=x/3;

zp2=((0.5*(h+x)*(y^2))+((y^3)/3))/(((h+x)*y)+(0.5*(y^2)));

za2=((0.5*x*(y^2))+((y^3)/3))/((x*y)+(0.5*(y^2)));

e2=(pp1*cosdp1)+(pa2*cosda2)-(pg*cosda1)-(pp2*cosdp2)-pq;

e3=(pp1*cosdp1*zp1)+(pp2*cosdp2*zp2)-(pg*cosda1*((h+x)/3))-(pa2*cosda2*za2)-pq*(1/3)*(h+x)*((kq+2*kq1)/(kq+kq1));

g=[e2; e3];

J=jacobian([e2, e3], [x, y]);

A=zeros(2,numel(LAM));

for i=1:numel(LAM)

del=1;

indx=0;

lam=0;

while del>1e-6 && tan(alphac)<(1/lam)

gnum = vpa(subs(g,[x,y,lam],[a(1),a(2),LAM(i)]));

Jnum = vpa(subs(J,[x,y,lam],[a(1),a(2),LAM(i)]));

delx = -Jnum\gnum;

a = a + delx;

del = max(abs(gnum));

indx = indx + 1;

end

Z(:,i)=double(a)

end