For the Euler's Theorem example given during class session (Sahil Sir), 17^81/100, why can't we use Cyclicity to find the remainder in this question? 81/4 is 20 and the remainder comes as 1. So, 17^1 is 17, and 17/100 gives 17 as the remainder.

In the second example of the same class, where using both Remainder and Euler Theorem, we could have used Cyclicity to derive the answer. The question was 21^865/17. Here, 865 divided by 4, gives 1 as the remainder. So, 21^1 is 21, and 21/17 gives 4 as the remainder.

So, are there any exceptions or reasons for not using the Cyclicity method?

Hi

It will be beneficial for us if you could attach a screenshot of the questions you are talking about.

Regardless, QA and mathematics in general is a subject that allows for multiple methods to be used to arrive at the same result. Similarly, for finding remainders, cyclicity is one of the multiple ways by which you could approach the question. However, keep in mind that the CAT requires precision as well as speed - so the most efficient method should be the method of choice. Maybe Sir didn't use cyclicity because it wasn't efficient enough.

Hope this helps.

@rahul So Sir, basically we can use Cyclicity as well for the same question. Also, wanted to know that are there any exceptions if we use the Cyclicity method. Like will there be certain questions wherein which we can't use the Cyclicity method?

Hope you answer this.