The coefficient of x2 in the expansion of (2x2+ 1x )10, x 0, is :
- 3240
- 3360
- 3480
- 3600
Answer
(2) 3360
Solution
Tr+1=10Cr (2x2 )10-r ( 1x )r=10Cr 210-rx20-3r
For x2: 20-3r=2 r=6
Coefficient =10C6 24=210 16=3360
Answer: (2)
The coefficient of x2 in the expansion of (2x2+ 1x )10, x 0, is :
(2) 3360
Tr+1=10Cr (2x2 )10-r ( 1x )r=10Cr 210-rx20-3r
For x2: 20-3r=2 r=6
Coefficient =10C6 24=210 16=3360
Answer: (2)
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