Summations

Question 1

What do u do when the r value is not equal to 1

Answer 1

Split each sum eg. R^2 + r
Then make the first one n then the next one n-1
Then work out each one separately and merge them back together

Question 2

What do u do when the top part is n-2 not n

Answer 2

Do the same thing but sub in n-2