4. How many students have interest in Art and Mathematics?
Answers
Answered by
0
Answer:
9
Step-by-step explanation:
Then,
S
n
=(x+
x
1
)
2
+(x
2
+
x
2
1
)
2
+(x
3
+
x
3
1
)
2
+....+(x
n
+
x
n
1
)
2
=(x
2
+
x
2
1
+2)+(x
4
+
x
4
1
+2)+(x
6
+
x
6
1
+2)+.....+(x
2n
+
x
2n
1
+2)
=(x
2
+x
4
+x
6
+.....+x
2n
)+(
x
2
1
+
x
4
1
+
x
6
1
+.....+
x
2n
1
)+
n times
(2+2+....+n)
=x
2
(
x
2
−1
(x
2
)
n
−1
)+
x
2
1
(
(1/x
2
)−1
(1/x
2
)
n
−1
)+2n
=x
2
(
x
2
−1
x
2n
−1
)+
x
2n
1
(
1−x
2
1−x
2n
)+2n
=x
2
(
x
2
−1
x
2n
−1
)+
x
2n
1
(
x
2
−1
x
2n
−1
)+2n
=(
x
2
−1
x
2n
−1
)(x
2
+
x
2n
1
)+2n.
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