Sail E0 Webinar
Question
Find the equation with roots 2, 3, 4, 5 and 6.
Options:
A .  x5+72x4+140x3−580x2+1024x+720=0
B .  x5−20x4+155x3−580x2+1044x−720=0
C .  x5+20x4+165x3+585x2−1044x−720=0
D .  x5−30x4−165x3−680x62−1024x+720=0
Answer: Option B
:
B
Let the equation be Ax5+Bx4+Cx3+Dx4+Ex+F=0
Sum of the product of the roots taken 1 at a time =BA
=BA
Sum of the product of the roots taken 2 at a time =CA
(2×3)+(2×4)+(2×5)+(2×6)+(3×4)+(3×5)+(3×6)+(4×5)+(4×6)+(5×6)=CA
155=CA
Sum of the product of the roots taken 3 at a time =DA
(2×3×4)+(2×3×5)+(2×3×6)+(2×4×5)+(2×4×6)+(2×5×6)+(3×4×5)+(3×4×6)+(3×5×6)+(4×5×6)=DA
580=DA
Sum of the product of the roots taken 4 at a time =EA
(2×3×4×5)+(2×3×4×6)+(2×3×5×6)+(2×4×5×6)+(3×4×5×6)=1044
1044=EA
Sum of the product of the roots taken 5 at a time=FA
(2×3×4×5×6)=FA
720=FA
Take A=1. Then B= -20,C=155, D= -580, E=1044, F=-720

Was this answer helpful ?
Next Question

Submit Solution

Your email address will not be published. Required fields are marked *

More Questions on This Topic :


Latest Videos

Latest Test Papers