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NDA · Maths · Circles
NDA Circles — Formulas 2
Question
1
of 12
1.
For
x
2
+
y
2
+
2
g
x
+
2
f
y
+
c
=
0
x^2+y^2+2gx+2fy+c=0
x
2
+
y
2
+
2
g
x
+
2
f
y
+
c
=
0
, which gives the centre and radius?
A
x
2
+
y
2
+
2
g
x
+
2
f
y
+
c
=
0
⇒
centre
(
−
g
,
−
f
)
,
r
=
g
2
+
f
2
−
c
x^2+y^2+2gx+2fy+c=0 \;\Rightarrow\; \text{centre }(-g,-f),\;\; r=\sqrt{g^2+f^2-c}
x
2
+
y
2
+
2
g
x
+
2
f
y
+
c
=
0
⇒
centre
(
−
g
,
−
f
)
,
r
=
g
2
+
f
2
−
c
B
centre
(
g
,
f
)
,
r
=
g
2
+
f
2
−
c
\text{centre }(g,f),\;\; r=\sqrt{g^2+f^2-c}
centre
(
g
,
f
)
,
r
=
g
2
+
f
2
−
c
C
centre
(
−
g
,
−
f
)
,
r
=
g
2
+
f
2
+
c
\text{centre }(-g,-f),\;\; r=\sqrt{g^2+f^2+c}
centre
(
−
g
,
−
f
)
,
r
=
g
2
+
f
2
+
c
D
centre
(
−
2
g
,
−
2
f
)
,
r
=
g
2
+
f
2
−
c
\text{centre }(-2g,-2f),\;\; r=g^2+f^2-c
centre
(
−
2
g
,
−
2
f
)
,
r
=
g
2
+
f
2
−
c
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