\(96 \) can be expressed as the sum or difference of two numbers whose powers are easier to calculate and then, binomial theorem can be applied.
It can be written that, \(96 = 100 - 4\)
∴ \((96)^3=(100-4)^3\)
=\(^3C_0(100)^3 - ^3C_1(100)^2(4)+ ^3C_2(100)(4)^2 - ^3C_3(4)^3\)
=\((100)^3-3(100)^2(4)+3(100)(4)^2-(4)^3\)
=\(1000000-120000+4800-64\)
= \(884736\)
If a and b are distinct integers, prove that a - b is a factor of \(a^n - b^n\) , whenever n is a positive integer.
[Hint: write\( a ^n = (a - b + b)^n\) and expand]
Find the mean and variance for the following frequency distribution.
Classes | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
Frequencies | 5 | 8 | 15 | 16 | 6 |