Question

what is the difference between
s =n/2[2a+(n-1)d)
and
s=n/2(a+l)
how we get to know that where we have to use which formula ​

Answer 1

Notice, you can retrieve a from the formula sn=n2(2a+(n−1)d) by plugging in n=1 . So a=s1 .

Notice, you can retrieve a from the formula sn=n2(2a+(n−1)d) by plugging in n=1 . So a=s1 .In fact, this is the formula for the sum of the first n terms of an arithmetic progression with first term a and common difference d . When n=1 , the sum of the first n terms is just its first term. ■

hope it will help uh ❤❤

Answer 2

I hope it is helpful

Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water.