In the expansion of (2−3x3)20 , if the ratio of 10th term to 11th term is 4522 , then x=

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

−23

−32

answer is C.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

Given expansion (2−3x3)20 is We have general term in the expansion (x+a)n (∴ Tr+1= nCr xn−r (a)r be the expansion of (x+a)n) 10th term: T10=T9+1=20C9(2) 11(−3x3)9 T10=T9+1=20C9(2) 11(−3)9(x3)9 11th term:T11=T10+1=20C10(2)10(−3x3)10 T11=T10+1=20C10(2)10(−3)10(x3)10 In the expansion of (2−3x3)20 , if the ratio of 10th term to 11th term is 4522 , thenGiven, T10T11=4522 ⇒20C9(2) 11(−3x3)920C10(2)10(−3x3)10=4522 (∴nCr=n!(n−r)! r!) ⇒20!9!11!×10!10!20!×2−3x3=4522 ⇒1011.2−3x3=4522 ⇒x3=20−33×2245=(−23)3 ⇒x=−23

Watch 3-min video & get full concept clarity