%P346.m:
syms a b c real
syms xA yA zA xB yB zB xC yC zC real
syms alfaA betaA gamaA alfaB betaB gamaB alfaC betaC gamaC real
ax = a * cos(alfaA);
ay = a * cos(betaA);
az = a * cos(gamaA);
bx = b * cos(alfaB);
by = b * cos(betaB);
bz = b * cos(gamaB);
cx = c * cos(alfaC);
cy = c * cos(betaC);
cz = c * cos(gamaC);
av = [ax ay az].';
bv = [bx by bz].';
cv = [cx cy cz].';
OA = [xA yA zA].';
OC = [xC yC zC].';
E1 = cross(OA,bv) + cross(av,OC);
E2 = cross(av,bv)+cv;
display(E1)
display(E2)
an = input('Modul a: ');
bn = input('Modul b: ');
cn = input('Modul c: ');
xAn = input('xA: ');
yAn = input('yA: ');
zAn = input('zA: ');
xBn = input('xB: ');
yBn = input('yB: ');
zBn = input('zB: ');
xCn = input('xC: ');
yCn = input('yC: ');
zCn = input('zC: ');
alfaAn = deg2rad(input('alfaA: '));
betaAn = deg2rad(input('betaA: '));
gamaAn = deg2rad(input('gamaA: '));
alfaBn = deg2rad(input('alfaB: '));
betaBn = deg2rad(input('betaB: '));
gamaBn = deg2rad(input('gamaB: '));
alfaCn = deg2rad(input('alfaC: '));
betaCn = deg2rad(input('betaC: '));
gamaCn = deg2rad(input('gamaC: '));
E1n = subs(E1, [a b c xA yA zA xB yB zB xC yC zC alfaA betaA gamaA alfaB betaB gamaB], [an bn cn xAn yAn zAn xBn yBn zBn xCn yCn zCn alfaAn betaAn gamaAn alfaBn betaBn gamaBn]);
E1n = eval(E1n);
display(E1n)
E2n = subs(E2, [a b c alfaA betaA gamaA alfaB betaB gamaB alfaC betaC gamaC], [an bn cn alfaAn betaAn gamaAn alfaBn betaBn gamaBn alfaCn betaCn gamaCn]);
E2n = eval(E2n);
display(E2n)

%S204.m:
function A = s204(a,h,b)
j=1;
for i=a:h:b
    if i<=-pi/2
        A(j,1)=i;
        A(j,2)=sin(i);
        j=j+1;
    end
    if i>-pi/2 && i<=pi/2
        A(j,1)=i;
        A(j,2)=cos(i);
        j=j+1;
    end
    if i>pi/2
        A(j,1)=i;
        A(j,2)=sin(i)*cos(i);
        j=j+1;
    end
end

%N204.m:
a=input('Inceputul intervalului:');
b=input('Sfarsitul intervalului:');
h=input('Pasul intervalului:');
A=s204(a,h,b);
plot(A(:,1),A(:,2))
disp('Valorile functiei sunt: ');
disp(A);

%ecuatie_grad_2.m:
function [x1 x2 ok]=ecuatie_grad_2(a,b,c)
if a==0
    ok=0;
    x1=0;
    x2=0;
else
    ok=1;
    if b==0
        x1=-i*sqrt(4*a*c)/2*a;
        x2=i*sqrt(4*a*c)/2*a;
    elseif c==0
        x1=-b/a;
        x2=0;
    else
        x1=(-b-sqrt(b^2-4*a*c))/2*a;
        x2=(-b+sqrt(b^2-4*a*c))/2*a;
    end
end
end

%ecuatie.m:
a=input('Coeficient x^2: ');
b=input('Coeficient x: ');
c=input('Coeficient liber; ');
[x1 x2 ok]=ecuatie_grad_2(a,b,c);
if ok==1
    disp('Solutiile ecuatiei sunt :');
    disp(x1);
    disp(x2);
else
    disp('Ecuatia nu este de gradul 2');
end