If a^2 – 5a + 1 =0 , the value of a^2 + 1/a^2
Answers
Answered by
0
Answer:
±5
29
a
2
−5a−1=0
=>a
2
−1=5a
=>a−
a
1
=5
Squaring both sides, we get
=>a
2
+
a
2
1
−2a×
a
1
=25
=>a
2
+
a
2
1
=25+2
=>a
2
+
a
2
1
=27
Now,
(a+
a
1
)
2
=a
2
+
a
2
1
+2a×
a
1
=a
2
+
a
2
1
+2
=27+2
=29
a+
a
1
=±
29
Now,
a
2
−
a
2
1
=(a+
a
1
)(a−
a
1
)
=(±
29
)(5)
=±5
29
Similar questions