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ZWMath›Elementary number theory›Primes and cryptography›Prime number theorem›ZW-PRIME-NUMBER-THEOREM-005
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AreaNumber theoryCourseElementary number theoryTopicPrimes and cryptography
Divisibility and factorization10
  • Bézout's identity
  • Extended Euclidean algorithm
  • Euclid's lemma
  • Fundamental theorem of arithmetic
  • Least common multiple
  • Infinitude of primes
  • Linear Diophantine equation
  • Greatest common divisor Discrete mathematics
  • Euclidean algorithm Discrete mathematics
  • Prime number Discrete mathematics
Congruences9
  • Complete residue system
  • Modular inverse
  • Linear congruence
  • Chinese remainder theorem
  • Fermat's little theorem
  • Euler's totient function
  • Euler's theorem
  • Wilson's theorem
  • Modular congruence Discrete mathematics
Orders and quadratic residues6
  • Multiplicative order
  • Primitive root
  • Quadratic residue
  • Legendre symbol
  • Euler's criterion
  • Law of quadratic reciprocity
Arithmetic functions5
  • Multiplicative arithmetic function
  • Divisor functions
  • Perfect number
  • Möbius function
  • Möbius inversion formula
Continued fractions and Diophantine equations4
  • Continued fraction
  • Convergent of a continued fraction
  • Pell's equation
  • Sum of two squares
Primes and cryptography3
  • RSA cryptosystem
  • Fermat primality test
  • Prime number theorem

Exercise · ZW-PRIME-NUMBER-THEOREM-005 · ★☆☆ Basic

What is the approximate value of π(100)?

Choose one option.

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  • B. 25

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Explanation

There are 25 primes less than or equal to 100. Choosing 100 confuses π(100) with the value of x itself.

Study Elementary number theory in ZWMath →

Review the concept: Prime number theorem

The prime number theorem describes the asymptotic behavior of π(x), the number of primes less than or equal to x, as x tends to infinity.

\[\pi(x) \sim \frac{x}{\ln x}\]

More practice problems: prime number theorem

  • ZW-PRIME-NUMBER-THEOREM-001 What does π(x) mean in the prime number theorem?
  • ZW-PRIME-NUMBER-THEOREM-002 What does the theorem say about the behavior of π(x) as x tends to infinity?
  • ZW-PRIME-NUMBER-THEOREM-003 Which symbol denotes that two functions are asymptotically equivalent?
  • ZW-PRIME-NUMBER-THEOREM-004 According to the theorem, what does the ratio π(x)/(x/ln x) tend to as x grows?
  • ZW-PRIME-NUMBER-THEOREM-006 If π(x) ~ x/ln x, what is the approximate estimate of π(1000) using x/ln x?
  • ZW-PRIME-NUMBER-THEOREM-007 What is the approximate probability that an integer near x = 1000 is prime, according to the theore…
  • ZW-PRIME-NUMBER-THEOREM-008 If p_n sim n ln n, what approximate estimate does the theorem give for the 100th prime?
  • ZW-PRIME-NUMBER-THEOREM-009 What is the approximate value of the ratio π(100)/(100/ln 100)?

← ZW-PRIME-NUMBER-THEOREM-004 ZW-PRIME-NUMBER-THEOREM-006 →

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