(Solved):   a little help Question 3 The first five triangular numbers are shown, where n represents ...

 

a little help

Question 3 The first five triangular numbers are shown, where n represents the number of dots in the base a the figure, and d (n) represents the total number of dots in the figure. 136 10 15 When n = 1, there is 1 dot. When ? = 2, there are 3 dots. When ? = 3, there are 6 dots. Notice th the total number of dots d (n) increases by n each time. Use induction to prove that d (n) = "(n-¹). n(n+1) 2 Part A Prove the statement is true for n = 1.