4U Maths Question Thread

[ellipse]

Thank you so much 

No worries!

[Kle123]

im gonna have alot questions for today  . I don't know how to do part b) for part a) however i got A(0,-b/tan(theta)) B(0,(a^2+b^2)tan(theta)/b). Sorry I don't have any answers to this exam paper

[RuiAce]

im gonna have alot questions for today  . I don't know how to do part b) for part a) however i got A(0,-b/tan(theta)) B(0,(a^2+b^2)tan(theta)/b). Sorry I don't have any answers to this exam paper

Hint: On scrap paper, start by considering a circle where AB IS the diameter of. Then, since A and B both lie on the y-axis, we know that the center also lies on the y-axis.

In fact, the coordinates of the center is not hard to find - it'll just be the midpoint of AB, which I will call M.

And we can easily find the length of MA, which is also the length of MB (as they are both radii). It falls to use the distance formula to check that MS is yet a third radius of the circle, where S is the point (ae, 0).

[dux99.95]

let the other root be 'a.'

By doing the sum of roots, a+i=(1+i)/(2-i)
By realising the RHS, we get 1/5+3i/5=a+i.
Now solving for 'a,' you get a=1/5(1-2i)

Omg!! THANK YOU You made it so simple

[hanaacdr]

Hi
Could i please get some help on this mechanics question
what is retardation?
thank youuu

[jamonwindeyer]

Hi
Could i please get some help on this mechanics question
what is retardation?
thank youuu

Perhaps the wrong screenshot? I'm seeing lots of Chemistry 

[jakesilove]

Hi
Could i please get some help on this mechanics question
what is retardation?
thank youuu

I know this isn't what it's supposed to be, but MAKE SURE TO INCLUDE YOUR STATES WHEN YOU WRITE CHEMICAL EQUATIONS!

[RuiAce]

I know this isn't what it's supposed to be, but MAKE SURE TO INCLUDE YOUR STATES WHEN YOU WRITE CHEMICAL EQUATIONS!

The man has a point

[hanaacdr]

WOOPS sorry
Here it is,

(Question 5)
A particle...

[Shadowxo]

WOOPS sorry
Here it is,

(Question 5)
A particle...

(Image removed from quote.)

Retardation is just deceleration. If you're still having trouble let us know

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If the tangent to the cruve x^2+2xy+y^5=4 is horizontal at P(X,Y), show that P is a unique solution to the equation X^5+X^2+4=0

what does unique solution mean?

[wu345]

Unique means nothing else like it i.e it's the only solution to the equation.
This of course makes sense when you think about it geometrically - the tangent only touches the ellipse at one point so there will be only one intersection point (i.e one unique solution to the given equation)

[ellipse]

Unique means nothing else like it i.e it's the only solution to the equation

oh ok so I need to show that it is the only real solution (ie all other roots are complex)?

or is sufficient to just implicitly differentiate (you get x+y=0) and sub it into the curve to get that equation (x^5+x^2+4=0)?

[wu345]

oh ok so I need to show that it is the only real solution (ie all other roots are complex)?

or is sufficient to just implicitly differentiate (you get x+y=0) and sub it into the curve to get that equation (x^5+x^2+4=0)?

I think it should be sufficient to differentiate and sub as long as you justify it (i.e tangent only intersects the ellipse once)

[ellipse]

I think it should be sufficient to differentiate and sub as long as you justify it (i.e tangent only intersects the ellipse once)

yup thanks