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find-such-a-polynomial-if-is-divided-by-x-2-then-the-remainder-is-5-if-it-isdivided-by-x-3-the-remainder-is-9-if-it-is-divided-by-x-4-the-remainder-is-13-if-divide-by-x-10-and-the-remaid




Question Number 94818 by student work last updated on 21/May/20
 find such a polynomial if is divided by (x−2) then the   remainder is 5, if it isdivided by (x−3) the remainder  is 9, if it is divided by (x−4) the remainder is 13, if   divide by (x−10) and the remaider becomes 37 and  if (x−(3/4)) divided by the remainder becomes zero?
findsuchapolynomialifisdividedby(x2)thentheremainderis5,ifitisdividedby(x3)theremainderis9,ifitisdividedby(x4)theremainderis13,ifdivideby(x10)andtheremaiderbecomes37andif(x34)dividedbytheremainderbecomeszero?
Commented by Rasheed.Sindhi last updated on 21/May/20
The required polynomial is 4x−3
Therequiredpolynomialis4x3
Commented by student work last updated on 21/May/20
what is the practice der?
whatisthepracticeder?
Commented by Rasheed.Sindhi last updated on 21/May/20
I shall write answer in detail soon.
Ishallwriteanswerindetailsoon.
Commented by student work last updated on 21/May/20
you show practice to i learn
youshowpracticetoilearn
Commented by mr W last updated on 21/May/20
4x−3 is correct, but not the only one  solution, i think.  i′ll post my solution later.
4x3iscorrect,butnottheonlyonesolution,ithink.illpostmysolutionlater.
Commented by Rasheed.Sindhi last updated on 21/May/20
Yes sir it′s linear answer, and  if I′ve done correct calculation  quadratic is not possible.Now I′m  tryingfor cubic solution...
Yessiritslinearanswer,andifIvedonecorrectcalculationquadraticisnotpossible.NowImtryingforcubicsolution
Commented by student work last updated on 21/May/20
please post me solution sir
pleasepostmesolutionsir
Answered by mr W last updated on 21/May/20
say the polynomial searched is f(x).  f(x) can be divided by (x−(3/4)) without  remainder, therefore  f(x)=g(x)(x−(3/4))  with g(x) being an other polynomial.    when f(x) is divided by (x−2) we get  remainder 5, that means  f(x)=p(x)(x−2)+5, i.e. f(2)=5,  f(2)=g(2)(2−(3/4))=5 ⇒g(2)=4  similarly  f(3)=g(3)(3−(3/4))=9 ⇒g(3)=4  f(4)=g(4)(4−(3/4))=13 ⇒g(4)=4  f(10)=g(10)(10−(3/4))=37 ⇒g(10)=4  that means  g(x)=k(x)(x−2)(x−3)(x−4)(x−10)+4  with k(x) being any polynomial.  ⇒f(x)=g(x)(x−(3/4))  ⇒f(x)=[k(x)(x−2)(x−3)(x−4)(x−10)+4](x−(3/4))  or  ⇒f(x)=[c(x)(x−2)(x−3)(x−4)(x−10)+1](4x−3)  with c(x) being any polynomial  (including any constant)
saythepolynomialsearchedisf(x).f(x)canbedividedby(x34)withoutremainder,thereforef(x)=g(x)(x34)withg(x)beinganotherpolynomial.whenf(x)isdividedby(x2)wegetremainder5,thatmeansf(x)=p(x)(x2)+5,i.e.f(2)=5,f(2)=g(2)(234)=5g(2)=4similarlyf(3)=g(3)(334)=9g(3)=4f(4)=g(4)(434)=13g(4)=4f(10)=g(10)(1034)=37g(10)=4thatmeansg(x)=k(x)(x2)(x3)(x4)(x10)+4withk(x)beinganypolynomial.f(x)=g(x)(x34)f(x)=[k(x)(x2)(x3)(x4)(x10)+4](x34)orf(x)=[c(x)(x2)(x3)(x4)(x10)+1](4x3)withc(x)beinganypolynomial(includinganyconstant)
Commented by student work last updated on 21/May/20
thanks dear
thanksdear
Commented by Rasheed.Sindhi last updated on 21/May/20
Great mrW sir!
GreatmrWsir!
Commented by Rasheed.Sindhi last updated on 21/May/20
f(x) is either linear or it has degree  greater than 4?
f(x)iseitherlinearorithasdegreegreaterthan4?
Commented by mr W last updated on 21/May/20
correct sir!
correctsir!correctsir!

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