Euler’s Totient Function (Solved Examples)
Network Security: Euler’s Totient Function (Solved Examples)
Topics discussed:
1) Definition of Euler’s Totient Function Ф(n) or Phi Function Phi(n).
2) Explanation on how to find the Ф(n).
3) Solved examples of finding Ф(n) for larger numbers using formulas.
4) Various scenarios of n in Ф(n) such as ‘n’ being prime, ‘n’ being a product of two prime, and ‘n’ is a product of composite-prime-composite combination.
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Пікірлер: 99
The last formula where phi(n) = n * ( 1 - 1/p) * ( 1 - 1/q) * ( 1 -1/r) .... where p,q,r.... are the distinct prime factors of n is applicable to all the cases. So it can be treated as the one and only required formula. PS: thanks for the great content.
369=>41*3*3; phi(369)=>369*(1-1/41)(1-1/3)=240 372=>31*3*2*2; phi(372)=>372*(1-1/31)(1-1/3)(1-1/2)=120
@hossammahmoud6821
Жыл бұрын
how did u know that u must use 3 and 41 for Φ(369)? how did u know that u must use 2, 3 and 31 for Φ(372)? how did u reach there?
@cs1-34devabalamb9
Жыл бұрын
@@hossammahmoud6821 he did prime factorization on 369 and 372
@amanmotghare7196
4 ай бұрын
thanks
Answer to H.W : 1 : Φ(369) = 240 2 : Φ(372) = 120 So, there are 240 and 120 positive integers that are less than 369 and 372 respectively, also relatively prime to 369 and 372 respectively.
@editorsam8813
Жыл бұрын
Write bro
@omop5922
Жыл бұрын
@@editorsam8813 right hota hai
You are one of the best teachers so far. Thanks for this amazing video that explains everything the simplest way.👏👏
very nice explanation sir. continue like this
Excellent lecture
Excellent lecture Thanks alot
Answers: 240,120
@Arihantdesai413
7 ай бұрын
Sure
Thank you so much sir.
Sir, It's my humble request 🙏🏻 Plz add more video in playlist of data structure. Plz plz🙏🏻🙏🏻🙏🏻🙏🏻
Great video
Thank you so much😊
yo thanks for teaching me this
My finals will be in a a few hours. Thank you for the clear explanation! :D
@Mahi-nz5ct
Жыл бұрын
Which event were you participating?
@parmarh3898
Жыл бұрын
Pass or failed?
Thanks sir👍👍
= phi(3 * 123) = phi (3² * 41¹) ; = 369 * (1 - 1/3) * (1 - 1/41) ; = 369 * 2/3 * 40/41; = 3 * 80 = 240; Thus, 240 numbers are the positive integers that are relatively prime which is less than the given, 369; = Phi(3 * 124) = phi(3 * 31 * 2²) ; = 372 * (1 - 1/3) (1 - 1/31) (1 - 1/2) ; = 372 * 2/3 * 30/31 * 1/2; = 12/6 * 60 = 120; Therefore, 120 positive numbers are relatively prime and lesser than the given, 372.
Thanks bro i learn it,👍..by the way ur answers 240 and 120.
Best explanation I’ve found for this. Thanks!
phi(369) = 2^2*41=240 phi(372)=2^2*3*31=120 thank you for this video ;)
@neelamyadav7609
2 жыл бұрын
I think there is 3^2*41 =240.
I love you so much sir
LIFE SAVER!!!
What if the prime numbers p and q are same? How do we calculate?
Sir pi of thousend lo 2,5 prime number so formula wrong sir second formula may substitute
for the solution of the homwork how did u know that u must use 3 and 41 for Φ(369)? how did u know that u must use 2, 3 and 31 for Φ(372)? how did u reach there?
@rnboy0
10 ай бұрын
You learn how to factorize a number from youtube then come
@ashutosh1727
6 ай бұрын
you need to study 7th class mathematics again
Great movie, however it would have been good to solve bigger number such as phi(33389)
The answer is (i) 240 ,there are 240 number less than 369 that are relatively prime to 369. (ii) 120 , there are 120 numbers less than 372 that are relatively prime to 372.
Thank you thank you thank soo much sir. .i want to touch your feet .. seriously i wasted 2 hour in internet for just learning this thing 😂😂😂
How to find for 761
Answer of homework questions 1. Phi(369)=240 2. Phi(372)=120
Solve for phi(25) is it same as n is prime! i.e. phi (25)= n-1=25-1=24?
@RichaSingh-sy7hz
2 жыл бұрын
But 25 is not a prime number. I think as it is 5^2, so we we take n=5. phi(5)=n-1, n=4.
Phi of 369 is 240 and phi of 372 is 120❤️
Ans:-Q1-240,Q2-120
phi(369)=240 phi(372)=120
How to solve phi(25) Can any body help
Can anyone share the full solution of the homework? I wanna see it
@PRITESHKRSRV
Жыл бұрын
369 = 3^2 X 41 Distinct primes = 3,41 phi(368) = 369 X (1-1/3) X (1-1/41) = 369 X 2/3 X 40/41 = 240 Same Approach for phi(372)
@pruthvirajgspruthvi4315
Жыл бұрын
@@PRITESHKRSRV but another 3 is not calculated y please explain me..👀
@adityarai30
Жыл бұрын
@@pruthvirajgspruthvi4315 use distinct prime formula discussed in video
if i solve phi(1000) according to second formula i was getting 4. note(here 2 and 5 both are prime numbers )
@PRITESHKRSRV
Жыл бұрын
Kid read the second formula again. product of 2 and 5 is not equal to 1000
∅(369) =240 ∅(372) =120 😊 thank you creators, always helping me to revise quickly before exams.. ❤
How can we cross check whether ans is correct or not?
@PRITESHKRSRV
Жыл бұрын
Apply Standard method, calculate GCD of each digit and verify. That's all you can
Answers are 240 and 120
1. 240 2. 120
240&120
how to find phi of 25
@shrutibiswas1530
8 ай бұрын
Using the 3rd formula. 25×(1-1/5)=20
phi(369)=240 , phi(372)=120
@sandrabm3224
2 жыл бұрын
how u got the 1st answer
❤️
Can anyone say of n=49, answer
@mehedihassanshimul2248
3 ай бұрын
42
369 = 123 * 3 = 122 * 2 = 244
@hardikkumarsingh
5 ай бұрын
123 is not a prime no. , so this is wrong
How you people got to know the factors of 369 and 372?
@subratamandal2924
4 ай бұрын
In this cases you have to calculate factors, by dividing starting from 2 and onwards
240 and 120
11:13 phi(1000) = 40
@renositon4344
2 жыл бұрын
400 po
224; and 330
240,120
Phi(27)
@mehedihassanshimul2248
3 ай бұрын
18
240 n 120
Sir but how would we solve for 25😢😢😢
@Varsha_Thomas
4 ай бұрын
Use the third formula. n*(1-1/p) = 25*(1-1/5) = 25*⅘ = 20 The second formula is not possible. We know that 25 = 5*5, however here p and q are NOT distinct. They should be distinct in order to use the second formula.
@Varsha_Thomas
3 ай бұрын
@user-kf1yq8nv8x but isn't the answer 20?👀
@Varsha_Thomas
3 ай бұрын
@user-kf1yq8nv8x But isn't the answer 20?
1:13
1. Φ(369) = 240 Prime Factors of 369 = [3 * 3 * 41] = [3^2 *41] Φ(369) = 3 * 3 * 41 * (1-1/3) * (1-1/41) = 3 * 3 * 41 * 2/3 * 40/41 = 3 * 2 * 40 = 240 2. Φ(372) = 120 Prime Factors of 372 = [2 * 2 * 3 * 31] = [2^2 * 3 * 31] Φ(372) = 2 * 2 * 3 * 31 * (1-1/2) * (1-1/3) * (1-1/31) = 2 * 2 * 3 * 31 * 1/2 * 2/3 * 30/31 = 2 * 1 * 2 * 30 = 120
@hossammahmoud6821
Жыл бұрын
how did u know that u must use 3 and 41 for Φ(369)? how did u know that u must use 2, 3 and 31 for Φ(372)? how did u reach there?
Phi(25)=20
@sathvicendra4108
2 жыл бұрын
How by using eulers
@sohagdhali827
2 жыл бұрын
@@sathvicendra4108 5^2=25 that's why 25*(4/5)=20
bi
What about the last formula ?? n=a×b.... Composite...where is s or b in the formula?// COMPLETELY WRONG FORMULA FOR THE LAST ONE!!
Pi(369)=60 pi (372)=60
Please start teaching FULL STACK DEVELOPMENT COURSE. I am learning now 😌. if you start it now , it will be helpful for many students who are preparing for placements.
@Umar-nl3ny
2 жыл бұрын
you are everywhere asking for something, pls take it easy on him and yourself
phi(369) = 240 phi(372) = 120
phi(369) = 240, phi(372) = 120
phi ( 369 ) = 240 phi ( 372 ) = 120
@sandrabm3224
2 жыл бұрын
how u got the 1st answer
@akarshmalhotra1154
2 жыл бұрын
@@sandrabm3224 factors of 369 are 3,41 . One of the factors are composite which means Case 3 is applicable i.e 369 * (1-1/3) * (1-1/41) = 240
@navinsingh2784
2 жыл бұрын
@@akarshmalhotra1154 But 3 and 41 both are prime so how it can fall under Case 3??
phi(369) = 240 phi(372) = 120