If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
@iLoveTorres said:bro thoda detail mein samjha do how to solve this types of questions
Algebra is my weak link 😃 Always end up taking long methods in these...ismein bhi I was doing some complex mess, eliminated 2 options, but couldn't choose between the other two!
regards
scrabbler
regards
scrabbler
@amresh_maverick said:If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
@amresh_maverick said:If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
2?
regards
scrabbler
regards
scrabbler
@amresh_maverick said:If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
2.
see,
a+b+c = -4/2
ab+bc+ac = -3/2
and abc = 1/2
open the brackets (1-a)(1-b)(1-c)
u get 1-abc + ab+bc+ac - (a+B+c)
put the values .. u'll get 2.
sorry edit. it's 1. not 2.
see,
a+b+c = -4/2
ab+bc+ac = -3/2
and abc = 1/2
open the brackets (1-a)(1-b)(1-c)
u get 1-abc + ab+bc+ac - (a+B+c)
put the values .. u'll get 2.
sorry edit. it's 1. not 2.
@scrabbler said:Algebra is my weak link Always end up taking long methods in these...ismein bhi I was doing some complex mess, eliminated 2 options, but couldn't choose between the other two!regardsscrabbler
mine are algebra and geometry. the latter i feel is your strong point 😃
@iLoveTorres said:mine are algebra and geometry. the latter i feel is your strong point
Haan Geometry and PnC used to be my weak links, then I worked like mad on them, ab woh manage ho jaata hai mostly ... algebra I was too lazy 
regards
scrabbler
regards
scrabbler
@ChirpiBird said:2.see, a+b+c = -4/2ab+bc+ac = -3/2and abc = 1/2open the brackets (1-a)(1-b)(1-c)u get 1-abc + ab+bc+ac - (a+B+c)put the values .. u'll get 2.
mam how do you decide the "+"&"-" signs for the coeff or x^2,x,const term.. i usually end up making mistake in deciding the sign.. can you help me with it
@ChirpiBird said:2.see, a+b+c = -4/2ab+bc+ac = -3/2and abc = 1/2open the brackets (1-a)(1-b)(1-c)u get 1-abc + ab+bc+ac - (a+B+c)put the values .. u'll get 2.
1 -1/2 -3/2 -(-2)= 1/2-3/2 +2 =-2/2 +2=1 ???
@iLoveTorres said:mam how do you decide the "+"&"-" signs for the coeff or x^2,x,const term.. i usually end up making mistake in deciding the sign.. can you help me with it
left to right starting from b onwards.. (-) then (+) .. .alternatively.
ax^2+bx+c =0
rts are say p,q
p+q= -b/a
pq=c/a ..
similarly for 3 wala eq.
ax^3+bx^2+cx+d=0
pqr roots
p+q+r=-b/a
pq+qr+pr= c/a
pqr=-d/a
ax^2+bx+c =0
rts are say p,q
p+q= -b/a
pq=c/a ..
similarly for 3 wala eq.
ax^3+bx^2+cx+d=0
pqr roots
p+q+r=-b/a
pq+qr+pr= c/a
pqr=-d/a
@amresh_maverick said:1 -1/2 -3/2 -(-2)= 1/2-3/2 +2 =-2/2 +2=1 ???
calculation dekhlo yar.. it's 2 am n i was watching exorcism of emily rose. Mind wasnt here. :P
method thik h. baaki calculation plz check kar lena.
method thik h. baaki calculation plz check kar lena.
@amresh_maverick said:If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
1 he kya ans..?
@ChirpiBird said:right to left starting from b onwards.. (-) then (+) .. .alternatively.ax^2+bx+c =0rts are say p,qp+q= -b/apq=c/a ..similarly for 3 wala eq.ax^3+bx^2+cx+d=0pqr rootsp+q+r=-b/apq+qr+pr= c/apqr=-d/a
yeh toh left to right hai :P
@iLoveTorres said:mam how do you decide the "+"&"-" signs for the coeff or x^2,x,const term.. i usually end up making mistake in deciding the sign.. can you help me with it
Alternate +/-.
Suppose roots are p, q, r, s the expression will be (x-p)(x-q)(x-r)(x-s)...
expansion will be x^4 - (1 at a time) x^3 + (2 at a time) x^2 - (3 at a time) x + (4 at a time) i.e. x^4 - (p + q + r + s) x^3 + (pq + pr + ps + qr + qs + rs) x^2 - (pqr + pqs + prs + qrs) x + (pqrs)
Example: cubic with roots 1, 2, 3 will be x^3 - 6x^2 + 11 x - 6
However if roots are -1, -2, -3 it will become x^3 + 6x^2 + 11 x + 6
regards
scrabbler
Suppose roots are p, q, r, s the expression will be (x-p)(x-q)(x-r)(x-s)...
expansion will be x^4 - (1 at a time) x^3 + (2 at a time) x^2 - (3 at a time) x + (4 at a time) i.e. x^4 - (p + q + r + s) x^3 + (pq + pr + ps + qr + qs + rs) x^2 - (pqr + pqs + prs + qrs) x + (pqrs)
Example: cubic with roots 1, 2, 3 will be x^3 - 6x^2 + 11 x - 6
However if roots are -1, -2, -3 it will become x^3 + 6x^2 + 11 x + 6
regards
scrabbler
@amresh_maverick said:If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
OA =1
x^2 + px +3=0 if roots are two successive odd natural nos, find the value of p ?
x^2 + px +3=0 if roots are two successive odd natural nos, find the value of p ?
@amresh_maverick said:If a , b, and c are the roots of 2x^3+4x^2 -3x-1=0 find tha value of (1-a)(1-b)(1-c)
aftr multplying it comes out 2 b 1-(a+b+c)+ab+bc+ac-abc
=1-(-2)+(-3/2)+(-1/2)=1
=1-(-2)+(-3/2)+(-1/2)=1
@vijay_chandola said:Arrange A and B by 2!permutation of 7 letters between A and B=P(24, 7)rest letters+1(AxxxxxxxB) can be arranged by (26-7-2+1)!=18!==> A total number of 2!*P(24, 7)*18! option 2)
rest letters +1.....yea 1 kaha se aia???pls elaborate
@amresh_maverick said:OA =1x^2 + px +3=0 if roots are two successive odd natural nos, find the value of p ?
4? roots are 1,3?