Higher Prelim Revision Help!!!!!!!!!!!!!!!!!!!!!!!!
Published November 27th, 2006 in homeworkI’ve been sitting by my computer now since 7.30pm. I’m off to chill for 45 mins. I’ll be back around 9.30pm to help anyone that needs it.
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Hi Mr S. I’ve just about finished my revision. The only question I’ve had real trouble with is one i found, don’t ask how at http://www.invergordon.highland.sch.uk/departments/maths/higher/homework/set1/mixed1.pdf. Its the differentication question 2. Its similar to question 5 on prelim revision 3, i didn’t have much trouble with that one but this one is tricky.
Nevermind, the link isn’t working and i think i’ve got it now, panic over
Hi sam. I’m glad to hear it. Unfortunately the link takes me nowhere. Is it definitely typed correctly? If you check it and get back to me I’ll help you out.
I’ve just realised that theres one question i was stuck on and was going to ask about- its question 4 on HW 3. I thought differentiicion but it gets me nowhere as i cant factorise it to find roots?
ok this may be a stupid question but when a question asks you to find the maximum and minimum values of a function what are they askin you to do?
For s.ps F’(x) = 0
0=54 - 16/x^3
multiply thorughout by x^3 to get something nicer possibly?
they want you to find the maximum and minimum values of the function .. so you find the stationary points and then find their natures to determine whether they are a max or a min. hope that helps?
ahhh okay thanks but if its a maximum t.p then is that the x value? so what would then be the minimum value?
Hey girv. Max/ min screams differentiate at me. Find the maximum and minimum turning points. I would imagine that the domain is limited (i.e. -10<x,20) and you may find your maximum or minimum values of the function at the extremities of the given domain (i.e when x = -10 or x =20). It’s hard to say without seeing the question. hope this is helpful.
ALSO, how do you work stupid geogebra without it telling me “invalid input”?
the max value of the function is the y (or f(x) ) .. then you plug your x value, u get by setting the derivative equal to zero, back into the original function to get your y co-ordinate/value.
Girv. rather than using y = in geogebra try F(x) =
ok yeah i get that i was getting confused and had a blonde moment. so what if it asks you for both the max and min tp and its a quadratic or if theirs only say a max tp?
That was easy. I was being silly and saying that x^3 times 0 = X^3. Doh! Thanks alot Mr S.
oh thanks mr s that works now! =]
if it’s a quadratic .. it will produce two values for x and hopefully one value of x will be the min TP and the other the max TP. If there’s only a max tp then it will most likely not ask for both a min and a max .. but just for the stationary points. sj
what did you get for that question sam??
thanks steve-o!! really not looking forward to tomorrow now…
Ye i think i went a bit overboard saying that it was easy- i’ve still not finished factorising the blasted thing
No problem! Don’t worry, it’ll fly by. All the best!! sj
hahaha did you differentiate and make it = 0 getting 54-(16/r^3)? pleeeease say you did! i then got it to r^3 = 8/27 but aint sure if its right…
Tis right giving r = cube root (8/27) = cube root 8/cube root 27 = 2/3. Wahey
Thats all i’ve got too- i’ve tried the polynomial division thingy with the table but i’ve got no where. Geogebra give a strange graph and this question is a nightmare.
Girv what were you on about before when you had a quadratic and were after a max and min value?
For crying out loud! Thats so easy i couldn’t see the answer.
oh i think i was being an idiot…hehe…okay im now doin the nature table for that question…wooooo
what’s easy?
my nature tables makes one think that i have found a stationary point not a turning point =[ this makes me sad.
i meant a point of inflexion!
If I was sitting my higher prelim I’d be so excited. I can’t believe you’re not looking forward to it Girv. I don’t know, the youth of today. When I was a lad… blah blah blah…..
I’m sure you will all do the best you can. I’m off to make a cup of hot chocolate. I think it’s probably a good time for you all to stop revising and get a good nights sleep. it will probably benefit you far more thatn sitting up all night revising. I’ll come back in 5 minutes to answer last questions then I’m off to bed.
I thought i had the answer, maybe i don’t, i thought it was (2/3,54) but maybe i got it wrong. Nevermind. Good luck Girv and thanks Mr S.
okay..my last question is
The cost of laying a pipeline…
oh never mind.
i’m off to cry myself to sleep!
no i’m not really and why on earth would i be excited to sit on an uncomfortable chair in a hall doing maths on a squeaky desk for however long it is! i don’t know…
byeeeeeeeeeeeeeeeeee
Hi Girv. Remember a radius cannot be zero or so if you’ve used zero to evaluate c’(r) it will yield a false result for you. try 1/8 or another fraction smaller than 2/3
I GOT THAT TOO SAM! that makes me happy! but i cant be bleeped and am going to bed now…good luck too!
Glad to hear that’s it for the night.
byeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
ugh you’re kidding. oh well never mind…
ugh you’re kidding. oh well never mind…also now every time i post a comment (which i have done a lot of tonight) i have tot ype in a wee code thing…suspicious..
Girv. I’ll edit the expletive from your last comment for you
I think closing down this blog would be a good idea
and I also think that the comments order has been switched or it could just be me.
This post or the whole blog Callum?
RevisionWorld http://www.revisionworld.co.uk has just uploaded some free videos onto its site for a whole range of maths questions. I hope these are useful.