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Education / Re: NEWLY ADMITTED UNIBEN STUDENTS 2013/2014 SESSION... by Calculusfx: 5:09pm On Jun 16, 2013
JungleboyT: My fwend choose uniben as 1st choice and had an aggregate 199 going 4 ecostat. plz wat hope doz he hv? Also wat score shud he aim 4 d putme if posibu d cut off is reduced?
...uniben can't accept <200
Education / Re: NEWLY ADMITTED UNIBEN STUDENTS 2013/2014 SESSION... by Calculusfx: 2:50pm On Jun 16, 2013
jazinogold: no @calculus
...thank you very much bro...
Education / Re: NEWLY ADMITTED UNIBEN STUDENTS 2013/2014 SESSION... by Calculusfx: 1:14pm On Jun 16, 2013
I heard that those candidates offering biology will be asked 10 mathematics questions...pls sir,i just want to ask that,will those offering maths be asked biology questions also?
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 1:10pm On Jun 16, 2013
Mbahchiboy: need ur assistance guys:: Integrate sqareroot(x^2+4x)dx
...NOTE:£...REPRESENTS THE INTEGRAL FUNCTION...the question is £sqrt x^2+4x.dx...make it a perfect square...so it becomes £sqrt x^2+4x+4-4.dx...which equals to £sqrt(x+2)^2 -2^2.dx...{NOTE...when in form of sqrtx^2+a^2,use substitution x=asinh@...in form of sqrta^2-x^2,use substitution x=asin@ and in form of sqrtx^2-a^2,use substitution x=acosh@}so,which one are we going to use now...x=acosh@...so back to where we stopped...£sqrt(x+2)^2-2^2.dx...then we substitute x+2=2cosh@.equation 1...substitute that,then it becomes £sqrt(2cosh)^2-4dx=£sqrt4cosh^2@-4dx=£sqrt4(cosh^2@-1)dx=£2sqrt(cosh^2@-1)dx...then let's go to hyperbolic functions...cosh^2@-sinh^2=1...therefore cosh^2@-1=sinh@...substitute it to where we stopped...£2sqrt(cosh^2@-1)dx...=£2sqrtsinh^2@.dx...=£2sinh@.dx...so,from equation 1...x+2=2cosh@...dx=2sinh@d@...then substitute that to where we stopped...£2sinh@.2sinh@d@...£4sinh^2@d@.equation x...from hyperbolic identities...cosh^2@+sinh^2@=cosh2@...(i) and from the first identity of hyperbolic functions...cosh^2@-sinh^2@=1...cosh^2@=sinh^2@+1...substitute that to (i)...cosh^2@+sinh^2@=cosh2@...then 1+2sinh^2@=cosh2@...therefore sinh^2@=(cosh2@-1)/2...then take that to equation x=£4sinh^2@.d@...£4.(cosh2@-1)2.d@...£2cosh2@-2d@...integrate normally to get...sinh2@-2@...equation 2...from hyperbolic identity...sinh2@=2sinh@cosh@...therefore it becomes 2sinh@cosh@-2@...equation 3...but sinh^2@=cosh^2@-1(as we did earlier)...and from equation 1...x+2=2cosh@,cosh@=(x+2)/2...substitute that...sinh^2@=(x+2)^2/4 -1...find the l.c.m and do it to get (x^2+4x)/4.{therefore sinh@=sqrt(x^2+4x)/2...and from equation 1...(x+2)/2=cosh@...therefore @=arccosh(x+2)/2}...back to equation 3...2sinh@cosh@-@...substitute those in bracket...to get 2*sqrt(x^2+4x)/2*(x+2)/2 - 2.arccosh(x+2)/2 + c...which becomes (x+2)sqrt(x^2+4x)/2-2arccosh(x+2)/2+c...IT'S SIMPLE...JUST SIT AND STUDY IT...
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 3:42pm On Jun 13, 2013
echibuzor:
.
.
This should be a geometric construction problem now? Or not...
...it's not bro,it just requires something called the position of centre of gravity of a triangle which is two-third of its altitude...
Education / Re: NEWLY ADMITTED UNIBEN STUDENTS 2013/2014 SESSION... by Calculusfx: 2:43pm On Jun 13, 2013
I'm a mechanical engineering aspirant@drake...add me on 2go with the username MATHEMAGICIAN
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 2:39pm On Jun 13, 2013
What's the centre of gravity of an equilateral triangle of side 24?...
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 2:38pm On Jun 13, 2013
echibuzor:
.
.
You are correct sir, I saw this question on another thread earlier today, I think this is a variation problem... All the same.. Good Job..
...thank you general...
Education / Re: Unilag 2013/2014/admission by Calculusfx: 2:32pm On Jun 13, 2013
What's the centre of gravity of an equilateral triangle of side 24cm?
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 2:25pm On Jun 13, 2013
rashywire: pls help luk @ dis
Ade cn do a certain job in 3hrs, Obi cn do d same job in 5hrs, and Audu cn do d same job in 7hrs. hw lng would d job take d three of dem working 2gether?
...ade can do it in 3 hours...therefore for 1 hour...ade will do 1/3 of the job...and for 1 hour obi will do 1/5 of the job while audu will do 1/7 of the job for just one hour...combining the work all of them will do in one hour...therefore it's 1/3 + 1/5 + 1/7=71/105...therefore for one hour they will do 71/105 of the job...and for the whole job to be completed they will do 105/71 as this;
1hr~~>71/105 therefore,
xhr~~>1...
Cross multiply from there to get 71x/105=1...therefore x=105/71 hours
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 1:37pm On Jun 13, 2013
busuyem: solve these questions:
1) If the standard deviation of a, b and c is d, what is the standard deviation of a+1, b+1 and c+1?
A. 3d B. 2d C. d/2 D. d+1 E. d
2)If the sum of the odd integers frm 1 to 50 is x and the sum of the even integers frm 1 to 50 is y, what id the value of x-y?
A. 50 B. 25 C. 0 D. 75 E. 15
...1.increase or decrease of each element in a data by a constant number or element has no effect on variance and standard deviation...so the answer is still d...2...for odd...1,3,5...and the nth term is 2n-1...so,we need to find the summation of that...therefore €(summation)2n-1.and from the rule,it becomes €2n-€1...therefore 2€n-€1...and €n=n(n+1)/2 while €1=n...therefore back to 2€n-€1...which is equal to n(n+1)-n...which is equal to n^2...therefore the formula for the sum of odd numbers is n^2...and there are 25 odd numbers in 50...so it will be 25 square to give 625(odd numbers)...therefore y=625 and using the same procedure...for the even numbers the sum is n(n+1) and there are 25 even numbers in 50...therefore 25*26=650...therefore x=650...therefore x-y=25
Education / Re: Unilag 2013/2014/admission by Calculusfx: 3:55pm On Jun 08, 2013
Mr Calculus: Squre root of X^x=x^rootx,
(x^x)^1/2=x^rootx,
X^x/2=x^rootx,
apply log to both side
logx^x/2=logx^rootx,
x/2logx=rootxlogx..logx cancel logx
x/2=rootx,x=2rootx
square both side
x^2=4x :x cancel x
-:x=4
Education / Re: Unilag 2013/2014/admission by Calculusfx: 3:41pm On Jun 08, 2013
hillsnite: Find the square root of 18-12root of 2
...just say sqrt of 18-12rut2=ruta-rutb...squar both sides 18-12rut2=(ruta-rutb)=a+b-2rutab...then compare with the question a+b=18...(1) and 2rutab=12rut2...therefore ab=72...(2)from this simultaneous equation a=12 when b=6 and a=6 when b=12...choose either of the two...let's choose a=12 when b=6...back to the question ruta-ruta=sqrt18-12rut2...therefore rut12-rut6=2rut3-rut6

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Education / Re: How To Calculate Quickly And Correctly In Mathematics by Calculusfx: 7:13pm On Jun 07, 2013
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Education / Re: Unilag 2013/2014/admission by Calculusfx: 7:07pm On Jun 07, 2013
Pls.masters here.how can i integrate x^x dx...
Education / Re: Unilag 2013/2014/admission by Calculusfx: 11:20am On Jun 07, 2013
Ortarico:

Good question! Another two perfect numbers are: 496 and 8,128.

...you are great bro

1 Like

Education / Re: Unilag 2013/2014/admission by Calculusfx: 8:22am On Jun 07, 2013
Ortarico:

Boss, I keep getting the same answer. Plz, show me my mistake boss.
.what's the question bro?
Education / Re: Unilag 2013/2014/admission by Calculusfx: 7:56am On Jun 07, 2013
labodinho: Morning ma swit ladies n smart guyz,aw ya nyt n hope una don dey dream of post-utme questnz sha? Jst dey post any questnz u dreamt bout........Trig for d breakfast.*LG.T*(as invented by Prof.Ortarico)Solve the following equatn in the range 0(D) less dan or =Tita less dan or =360(D)..NotesadD) means degree.(1)Sin tita=1/2 (2)_/2 (cos tita)-1=0 (3)Tan tita=-1 (4)Sinx=cosx (5)sin2x=0
NOTE...that in the first quadrant sin,cos and tan are all positive and the value €=@...in the second quadrant sin only is positive and €=180-@...in the third quadrant tan only is positive and €=180+@...in the fourth quadrant cos only is positive and €=360-@...1.sin@=1/2,take arcsin of both sides...sin.arcsin@=arcsin 0.5...but sin.arcsin=1...therefore @=arcsin 0.5;@=30D or 150D(cos sin is also positive in second quadrant)...2.i don't understand the question 3.tan@=-1...@=arctan -1=135D or 315D(cos tan is negative in second and fourth quadrant)...4.sin@=cos@...since sin(90-@)=cos@...so replace cos@ by sin(90-@)...therefore sin@=sin(90-@)...cancel sin...therefore @=90-@...therefore @=45D sin@=cos@ in the third quadrant cos both will give negative values=225D...5.sin2x=0...FIND arcsin of both sides sin.arcsin2x=arcsin0...2x=90.therefore x=45D...X is also equal to 90D,135D and 180D...
Education / Re: Unilag 2013/2014/admission by Calculusfx: 7:36am On Jun 07, 2013
Thank God.i meet a thread like this at last...maths gurus here...try this question as a welcom...PERFECT NUMBER.is a number in which all its factors except itself are added to itself...e.g 6 in which the factors are 1,2 and 3.add them together it gives 6...another example is 28...in which the factors are 1,2,4,7 and 14...added to give 28...FIND TWO MORE PERFECT NUMBERS...mail me at omoyeleolalekanjacob@gmail.com and 2go with MATHEMAGICIAN
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 7:10am On Jun 07, 2013
Lumidey: Hey guys. Pls I need a quick method to find d drterminant of a 4x4 matrix and ti find the eigen values
using cayley hamilton, expect frm d normal way cos its too long... Urgent reply pls
...try sarrus method bro...
Education / Re: NEWLY ADMITTED UNIBEN STUDENTS 2013/2014 SESSION... by Calculusfx: 7:06am On Jun 07, 2013
Pls.i heard that the postjamb is out...pls guys,is it true?
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 11:04pm On Jun 06, 2013
Mr Calculus: Bro in integratn if u av
integ2x it is dsam as 2integx.
if u av integx/2 it is dsam as 1/2integx.
u can try solving d exampls above u'l 5nd out dat its dsam.
I hope u undstand
.i know that...but you as mr calculus said integral 7^u du/cosx it's not possible to take cosx out just as if it's a constant.hadn't been it's ln2 or 7 or any constant...it can...but this one can not be done like that...THOUGH...i don't know the question but if someone gets it i will know

1 Like

Education / Re: Nairaland Mathematics Clinic by Calculusfx: 9:54pm On Jun 05, 2013
Mr Calculus:
integ7^sinxdx
Let u=sinx,du/dx=cosx,
dx=du/cosx,
integ7^sinx=integ7^udu/cosx,
recal integ a^x=a^x/Ina integ7^udu/cosx=1/cosxinteg7^udu=
1/cosx*7^u/In7+C
recal u=sinx..
1/cosx*7^sinx/In7+C=
7^sinx/cosxIn7 +C
...i understand this bro but it's not the answer coz you know u=sinx therefore du/dx=cosx...and dx=du/cosx...so the question becomes integral 7^u.du/cosx...you just took the cosx out of the integral function as if it's a constant...so,it can't be that bro...how can one integrate it from there...
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 11:14pm On Jun 04, 2013
Pls.help me on this integration...integral 7^sinx dx
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 8:09pm On Jun 04, 2013
Pls.my oga at the top here...help me with this question...2^x=2x...add me on 2go with the username Mathemagician(if you know you are a maths guru) and let's gain from one another
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 8:03pm On Jun 04, 2013
ladokuntlad: pls help me find d value of x if x^2=4x. show workings oooo. hint x=4
...to do that...x^2=4x.then,x^2-4x=0...factorize x out to give x(x-4)=0...therefore x=0 or x-4=0.therefore x=0 or x=4
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 7:59pm On Jun 04, 2013
labodinho: I dey feel u ma guy,i've been longing to hit a thread like dis to express ma feeling bout maths....i luv yur workings thr on our thread...kan u check dah qustn on our thread n see if u can help cos i've tried n i'm stuck in d middle.
...could you please tell me the thread bro
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 7:57pm On Jun 04, 2013
oladoya: bros this question is incorrect, it has to be in simultaneous form. Better still here comes the solving.....
2^x+3^x=13
introduce log.
Log2^x+3^x=log13
xlog2+xlog3=log13
x(log2+log3)=log13
xlog(2*3)=log13
xlog(6)=log13
x=log13/log6
log cancelled out and we have
x=13/6
x=2.16
app. 2
...thank you bro...it's just that you av already known the question that made you do it like that...moreso,in the logarithm,log(2^x + 3^x) can never be log2^x+log3^x
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 4:16pm On Jun 03, 2013
Mr Calculus:
Let u=sinx
-:du/dx=-cosx
-:dx=du/-cosx
integra7^sinx=integra7^u*du/-cosx,,
1/-cosxintegra7^u du recall::integra a^x=a^x/Ina,,,
:1/-cosx*7^sinx/In7+C =-7^sinx/cosxIn7
...thanx for the post mr calculus.but that's not the answer.though i don't know the answer...but from the begining.you said u=sinx and you found du/dx as -cosx...which is wrong...but assuming it's right...the question will become what when dx=du/cosx...since the question is integral 7^u dx...and u=sinx...then substitute dx.the question will turn to integral 7^u.du/cosx...then how will you do it from there bro...i'm confused
Education / Re: Nairaland Mathematics Clinic by Calculusfx: 2:17pm On Jun 03, 2013
Pls.help me solve this question.integral 7^sinx dx
Education / Re: How To Calculate Quickly And Correctly In Mathematics by Calculusfx: 7:42am On Jun 03, 2013
Pls.nairalanders.i want you to post more of this...if you don't know any...just type your comment to impress those that are typing it...there are still many more of these...i still lay emphasis on square,if you show that you like this thread...i will post multiplication to the extent that you can go to the examination hall without calculator...also need a magic to know trig. Functions sin and cos offhand.just comment on this thread...

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Education / Re: How To Calculate Quickly And Correctly In Mathematics by Calculusfx: 7:37am On Jun 03, 2013
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