The coefficient of x⁻²⁶ in the expansion of(x² - 2/x⁴)¹¹ is ??(prefer attached image if needed)
Sarvesh , 6 Years ago
Grade 12
Algebra> The coefficient of x⁻²⁶ in the expansion ...
1 AnswersSamyak Jain
Last Activity: 6 Years ago
To find : coefficient of x–26 in expansion of (x2 – 2/x4)11.
General term in eapansion of (a + b)n is Tr+1 = nCr . a(n – r). br
Here general term is Tr+1 = 11Cr . (x2)(11 – r). (– 2/x4)r = 11Cr . x2(11 – r). (– 2)r / x4r
i.e. Tr+1 = 11Cr . x22 – 2r – 4r. (– 2)r = 11Cr . x(22 – 6r). (– 2)r
For x– 26, x(22 – 6r) = x– 26 i.e. 22 – 6r = – 26 
6r = 48
or r = 8. Now put r = 8 in Tr+1. We get
T8+1 = 11C8 . x– 26. (– 2)8 = (11 ! / 8 ! 3!) . 28 x– 26 = (11.10.9 / 3.2) . 28 x– 26
T9 = 165 . 28 x– 26 = 330 . 27 x– 26
Provide a better Answer & Earn Cool Goodies
Enter text here...
LIVE ONLINE CLASSES
Prepraring for the competition made easy just by live online class.
Full Live Access
Study Material
Live Doubts Solving
Daily Class Assignments
Ask a Doubt
Get your questions answered by the expert for free
Enter text here...
Other Related Questions on algebra
Can we divide two vectors? If this is possible then how?
algebra
1 Answer Available
Last Activity: 1 Year ago
How do you write “the product of 18 and q” as an algebraic expression?
algebra
1 Answer Available
Last Activity: 1 Year ago
दहावीच्या आय सी एस इ विद्यार्थ्यांनी पुढे काय करायला पाहिजे
algebra
0 Answer Available
Last Activity: 2 Years ago