Qualification > Math

C2 DOUBT edexcel

(1/5) > >>

halosh92:
A circle has the equation
x2 + y2 + 8x ? 4y + k = 0,
where k is a constant.
(a) Find the coordinates of the centre of the circle. (2)
Given that the x-axis is a tangent to the circle,
(b) find the value of k.

for part b...how to get the radius exactly?

astarmathsandphysics:
Because the exapression completes the square as  (y+2)^2 it is two from the x acxis to the centre so the radius of the circle is 2.

halosh92:
can u explain how they got the angle here on wat basis?

halosh92:
Sketch on the same diagram the graphs of y = sin 2x and y = tan
2
x for x
in the interval 0 ? x ? 360°.
(b) Hence state how many solutions exist to the equation
sin 2x = tan
2
x ,
for x in the interval 0 ? x ? 360° and give a reason for your answer.

I have the answers i just need an explanation for part a
thx

astarmathsandphysics:
When I get up

Navigation

[0] Message Index

[#] Next page