Fig. 10

shows

a sketch

of

a circle

with

centre

C

(4,

2).

The

circle

intersects

the

x-axis

at

A(l,

0)

and

at

B.

y

C (4, 2)

•

Fig.

10

(i)

Write

down

the

coordinates

ofB.

[l]

(ii)

Find

the

radius

of

the

circle

and

hence

write

down

the

equation

of

the

circle

.

[4]

(iii)

AD

is a diameter

of

the

circle.

Find

the

coordinates

of

D.

[2]

(iv)

Find

the

equation

of

the

tangent

to

the

circle

at

D.

Give

your

answer

in

the

form

y

=

ax+b​