if a is not equal to zero and (a-1/a)=4, find,a²+(1/a²)
Answers
Answer:
the answer is is 18
Step-by-step explanation:
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Answer:
How can I solve the following problem: If a-1/a=5, then a^2-1/a^2=?
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supposed to be the right answer in one method,
If a-1/a=5 the a-1=5a
-1=5a-a which is -1=4a which is a=-1/4 ————1
a²-1/a² is (-1/4)² -1/(-1/4)² which is 1/16 -1/1/16.
-15/16 / 1/16
Applying another method from given condition in problem.
Other right answer is a-1/a=5—Eq1
So squaring both sides
We get a² -2a/a +1/a² which is a² +1/a² -2=5×5
Which further is a²+1/a²-2=25—Eq2
Now adding 4 to both sides
a²+1/a²-2+4=25+4
Which is a²+2+1/a²=29
Further square root of both sides
√a²+2+1/a²=√29
a+1/a=√29
Now in problem the then asked what is a²-1/a² is (a+1/a)(a-1/a)
a+1/a ×a-1/a
Whereas in question a-1/a=5 and a+1/a=√29 is proved
So +-5√29 is Answer.