Help with maths question GCSE
So there’s a maths question and I got an answer but it is wrong
So it says
Find the exact coordinates of the two intersections of the line y=2x
And the circle is x^2+y^2= 30
I keep getting the answers +-root 30 for x and +- 2 root 4
The correct answer is +-root six in the place of root 30
Can someone please explain this to me?
So it says
Find the exact coordinates of the two intersections of the line y=2x
And the circle is x^2+y^2= 30
I keep getting the answers +-root 30 for x and +- 2 root 4
The correct answer is +-root six in the place of root 30
Can someone please explain this to me?
Hi!
to find the intersections, substitute y=2x into the circle equation
x^2 + (2x)^2 = 30
(expand the square)
x^2 + 4x^2 = 30
(simplify by joining the x^2)
5x^2 = 30
(divide by 5 to get x^2)
x^2 = 6
(square root the 6 to get x alone, remember that a square root has a + and - solution)
x = +-root(6)
to find the intersections, substitute y=2x into the circle equation
x^2 + (2x)^2 = 30
(expand the square)
x^2 + 4x^2 = 30
(simplify by joining the x^2)
5x^2 = 30
(divide by 5 to get x^2)
x^2 = 6
(square root the 6 to get x alone, remember that a square root has a + and - solution)
x = +-root(6)
Original post by killuak
Hi!
to find the intersections, substitute y=2x into the circle equation
x^2 + (2x)^2 = 30
(expand the square)
x^2 + 4x^2 = 30
(simplify by joining the x^2)
5x^2 = 30
(divide by 5 to get x^2)
x^2 = 6
(square root the 6 to get x alone, remember that a square root has a + and - solution)
x = +-root(6)
to find the intersections, substitute y=2x into the circle equation
x^2 + (2x)^2 = 30
(expand the square)
x^2 + 4x^2 = 30
(simplify by joining the x^2)
5x^2 = 30
(divide by 5 to get x^2)
x^2 = 6
(square root the 6 to get x alone, remember that a square root has a + and - solution)
x = +-root(6)
Thank u sooo much💕💕💕
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