The first five triangular numbers are shown, where n represents the number of dots in the base of the figure, and represents the total number of dots in the figure.When n=1, there is 1 dot. When n=2, there are 3 dots. When n=3 , there are 6 dots. Notice that the total number of dots increases by n each time.Use induction to prove that d(n) = n(n+1)/2.Part AProve the statement is true for n=1 .Type your answer in the box.
