x
2
+
y
2
=
16
...
...
...
...
...
...
.
.
(
1
)
x + y = 4 (2)
rearrange (2) to y = 4 - x (could do x = 4 - y )
substitute y = 4 - x into (1)
hence:
x
2
+
(
4
−
x
)
2
=
16
⇒
x
2
+
16
−
8
x
+
x
2
=
16
and
2
x
2
−
8
x
+
16
−
16
=
0
⇒
2
x
2
−
8
x
=
0
factor and solve : 2x(x - 4 ) = 0
⇒
x
=
0
,
x
=
4
substitute these values into y = 4 - x , to find corresponding values of y.
x = 0 : y = 4 - 0 = 4 → (0 , 4)
x = 4 : y = 4 - 4 = 0 → (4 , 0 )
These are the points of intersection with the line x +y = 4 and the circle
x
2
+
y
2
=
16
Answer link
Объяснение:
// PascalABC.NET 3.0, сборка 1073
const
sb='bcdfgjklmnpqrstvwxz';
s='Computer programming is a process of computer programs creation';
var
i,n:integer;
s1,sn,t:string;
begin
i:=1;
while s[i]<>' ' do Inc(i);
s1:=Copy(s,1,i-1);
n:=Length(s); i:=n;
while s[i]<>' ' do Dec(i);
sn:=Copy(s,i+1,n-i);
t:='';
for i:=1 to Length(s1) do
if Pos(s1[i],sb)>0 then t:=t+s1[i];
s1:=t;
t:='';
for i:=1 to Length(sn) do
if Pos(sn[i],sb)>0 then t:=t+sn[i];
sn:=t;
t:='';
for i:=1 to Length(s1) do
if Pos(s1[i],sn)>0 then
if Pos(s1[i],t)=0 then t:=t+s1[i];
for i:=1 to Length(t) do Write(t[i],' ');
Writeln
end.
Тестовый прогон:
t r
2. "Нормальное" решение
// PascalABC.NET 3.0, сборка 1073
const
sb='bcdfgjklmnpqrstvwxz';
s='Computer programming is a process of computer programs creation';
begin
var a:=s.ToWords(' ');
a[0].Intersect(a[a.Length-1]).Where(x->Pos(x,sb)>0).Println(',')
end.
Тестовый прогон:
t,r