What is the value of 2 + 2 + 2^2 + 2^3 + 2^4 + 2^5 + 2^6 + 2^7 + 2^8? [/b}
Got the correct ans by the long long long approach..Shorter way??
Got the correct ans by the long long long approach..Shorter way??
Hey uptowngirl!
Look at the part 2+2. It is 4, right ? or 2^2.
Hence, we can factor 2^2 from two first figures.
i mean
[2^2+2^2]+2^3...=2^2(1+1)+2^3.....=2*2^2+2^3...=2^3+2^3+2^4...
Notice since that moment factoring 2^n will result in increasing of the next number's power by 1 at a time.
4 5 6 7 8 9 ===> 2^9 is your answer.
