samarth1222
Hi,
I have a doubt in the number properties how do we find out REMAINDER FOR A LARGE EXPONENT? example 92^60/15. In this example, if we have to find the remainder of the given equation how do we solve it?
Thanks
Hey! so Remainder for large exponents, especially questions of the format similar to the one you posted need a little playing around with numbers
Ok so we have \(\frac{92^{60}}{15}\): Now, in similar questions, we need to modify the numerator into a sum of two numbers so that one of those numbers is divisible by the denominator and then we have a smaller number to deal with (92 = 90 + 2)
\(\frac{92^{60}}{15} = \frac{(90+2)^{60}}{15}\)
\(\frac{90^{60}}{15} + \frac{2^{60}}{15}\)
Now, we know that 90 is divisible by 15 so that part will leave 0 as remainder, and we are left with \(2^{60}\) divided by 15
Let us see remainders of powers of 2, when divided by 15 to see if there is a pattern or not
\(2^1 = 2\); Remainder = \(2\)
\(2^2 = 4\); Remainder = \(4\)
\(2^3 = 8\); Remainder = \(8\)
\(2^4 = 16\); Remainder = \(1\)
\(2^5 = 32\); Remainder = \(2\)
\(2^6 = 64\); Remainder = \(4\)
\(2^7 = 128\); Remainder = \(8\)
\(2^8 = 256\); Remainder = \(1\)
As we can see there is a pattern forming for remainders of power of 2, when divided by 15 : {2,4,8,1} repeating with a cyclicity of 4
So 60 = 4*15
So 2^60 divided by 15 will leave us a remainder of 1
Answer = 1