JAMIA 2022 — Mathematics PYQ
JAMIA | Mathematics | 2022The coefficient of y in the expansion of (y2+yc)5 is
Choose the correct answer:
- A.
20c
- B.
10c3
(Correct Answer) - C.
10c
- D.
20c2
10c3
Explanation
Step 1: General Term Formula
The general term Tr+1 in the expansion of (a+b)n is given by:
Tr+1=(rn)an−rbr
Here:
-
n=5
-
a=y2
-
b=yc=cy−1
Step 2: Substitute the Values
Tr+1=(r5)(y2)5−r(cy−1)r
Tr+1=(r5)y10−2r⋅cry−r
Tr+1=(r5)cry10−3r
Step 3: Find r for the Coefficient of y
We need the power of y to be 1. Therefore, set the exponent of y equal to 1:
10−3r=1
3r=9
r=3
Step 4: Calculate the Coefficient
Now, substitute r=3 into the coefficient part of the general term:
Coefficient=(35)c3
Calculate (35):
(35)=2×15×4=10
So, the coefficient is:
10c3
Final Answer:
The coefficient of y is 10c3.
Explanation
Step 1: General Term Formula
The general term Tr+1 in the expansion of (a+b)n is given by:
Tr+1=(rn)an−rbr
Here:
-
n=5
-
a=y2
-
b=yc=cy−1
Step 2: Substitute the Values
Tr+1=(r5)(y2)5−r(cy−1)r
Tr+1=(r5)y10−2r⋅cry−r
Tr+1=(r5)cry10−3r
Step 3: Find r for the Coefficient of y
We need the power of y to be 1. Therefore, set the exponent of y equal to 1:
10−3r=1
3r=9
r=3
Step 4: Calculate the Coefficient
Now, substitute r=3 into the coefficient part of the general term:
Coefficient=(35)c3
Calculate (35):
(35)=2×15×4=10
So, the coefficient is:
10c3
Final Answer:
The coefficient of y is 10c3.

