Find the calue of 1+2+3+4+5------------------------------+45
Answers
Answered by
1
Sum of 1st n natural numbers = n(n+1)/2 N=45 45×46/2 45×23 =1035
CoruscatingGarçon:
brainliest pls
Answered by
0
1−2+3−4+5+...+43−44+451−2+3−4+5+...+43−44+45
=(1−2)+(3−4)+(5−6)+...+(43−44)+45=(1−2)+(3−4)+(5−6)+...+(43−44)+45
Here we group together every other term. These are pairs of numbers that sum to -1. There are 22 of these pairs altogether, plus the 45 at the end.
=(−1)+(−1)+(−1)+...+(−1)+45=(−1)+(−1)+(−1)+...+(−1)+45
=22(−1)+45=22(−1)+45
=23=23
Hope this helps!
=(1−2)+(3−4)+(5−6)+...+(43−44)+45=(1−2)+(3−4)+(5−6)+...+(43−44)+45
Here we group together every other term. These are pairs of numbers that sum to -1. There are 22 of these pairs altogether, plus the 45 at the end.
=(−1)+(−1)+(−1)+...+(−1)+45=(−1)+(−1)+(−1)+...+(−1)+45
=22(−1)+45=22(−1)+45
=23=23
Hope this helps!
Similar questions