Use Mathematical Induction to prove the sum of Arithmetic Sequences: C(a + (j- 1)d) = 7(2a + (n -1)d) j=1 Hint: First write down what P(1) says and then prove it. Then write down what P(k+1) says and prove that using the fact that P(k) is true. 1 P(1) says C(a +(j -1)d) = j=1 k+1 P(k+1) says C(a + (j-1)d) =