229k views
0 votes
Let p be a prime number greater than 2000, and let x = √p. Which of the following expressions represents a rational number?

a) p/x
b) x^2/p
c) x/p
d) p^2/x

User Adrihanu
by
8.0k points

1 Answer

1 vote

Final answer:

Among the expressions given, (b) x²/p represents a rational number, which simplifies to 1 because x² is the same as p for a prime number p greater than 2000.

Step-by-step explanation:

The student asks to evaluate which of the given expressions represents a rational number if 'p' is a prime number greater than 2000 and 'x' is the square root of 'p' (x = √p). To be a rational number, the expression must equal a fraction where both the numerator and the denominator are integers and the denominator is not zero.

Looking at option (a), p/x, we can rewrite it as p·(1/√p), which simplifies to √p. Since 'p' is prime and larger than 2000, √p is not an integer, so (a) is not rational.

Option (b), x²/p, becomes p/p, since x² is the same as p (√p times itself). This expression does indeed represent a rational number because p/p simplifies to 1, which is a rational number.

For option (c), x/p, we get √p/p, which is not rational since √p is not an integer and thereby the expression does not represent a ratio of two integers.

Lastly, option (d), p²/x, rewrites as p²/√p, simplifying to p·√p, which equals to p·p, and is indeed an integer but not rational as it does not have a non-zero integer denominator.

In conclusion, the expression which represents a rational number from the given options is (b) x²/p.

User Smoothware
by
7.9k points