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is that meant to be all under 1 for the LHS?

but i do... :confused:

Ok here's another one lol P(asec@,btan@) lies on the hyperbola. The tangent at P cuts the x-axis at X and the y-axis at Y. Show that PX/PY = sin2@ and deduce that if P is an extremity of a latus rectum, then PX/PY = (e2-1)/e2 I've done the first bit, but for the second bit, do all i have to do...

yes... very much :( so many teachers and students that i don't want to leave :(

thx guys

Okay can someone please do this question... P(acos @, bsin@) and Q(acos %, bsin%) lie on an ellipse. Show that if PQ subtends a right anle at (a,0) then tan(@/2)tan(%/2)=-b2/22. I know what i have to do but i just can't do it... if that makes sense :confused:

yea thats what im gna have to say

sucked in fool :)

is that right :confused:

i meant to say that "I think yop're assuming that the train is stationary" but obviously you aren't :confused: Still though, i think that they would have to either strike at the same time because it doesn't look like the train is travelling at relativistic speeds. About the new reference...

Well you can define Observer A a new intertial frame of reference that suits both A and B. A is in relative motion to the lightning strike and so is B, therefore, they are in the same inertial frame of reference. If the question says that both strikes hit the train at both ends then i think we...

ok ok OMG i got it but this time i left out the e... I thought you had to put e in the equation?

Nah i get 80x2/81 - 16x/9 + y2=0 but the answer is x2/9 + y2/8=1 No, this is for the equation of an ellipse :confused: so it has an eccentricity 0<e<1...

Well im going to have to say that they both see the lightning strikes the carriage at the same time. Reason being is that the lightning occurs in an inertial frame of reference where both observers are and because the question says that lightning strikes the back and front.

I think the geometry proofs are often reserved for things dealing with angles or straight lines intercepting each other. To be honest i haven't seen many :confused: for this question, you'd do something like this... S(3): For a 3-sided polygon (triangle, with angles A,B,C), the...

How can he see one lightning hit first while the other one is delayed if they both travel at the same speed of light :confused: Even if that were to happen aren't you assuming that the train is stationary? Because, otherwise, the train would have moved infront of the lightning strike behind it...

okay i have no idea what i am doing wrong but i cannot for the life of me get this answer right even though i'm pretty sure everything is right. Find the locus of a variable point P(x,y) which moves so that its distance from (1,0) is one third its distance from x=9. Don't you let...

Observer A sees the lightning strike the train simultaneously because he is in the inertial frame of reference. Observer B sees the lightning occur simultaneously, but i think he sees only the front being struck by lightning as length contraction predicts that the train carriage will shorten...

hmmmm ok next question... In a flock of 1000 chickens, the number P infected with a disease at time t years is given by P=1000/(1+ce-1000t) where c is a constant. i) Show that, eventually, all the chickens will be infected. ii) Suppose that when time t=0, exactly one chicken was infected. After...

I can't help it :( Okay im not sure what i have to do with the y=1/x graph but i can show the other bit ... 1/(k+1) < [ln x]k+1k < 1/k {after integration} .:e1/(k+1)< 1 + 1/k < e1/k by drawing the graphs you see that this is true .: the intial statement is true.