Problem 2 with explanation Problem 2: Find the sum of the Series 1 1.3 + 2 1.3.5 + 3 1.3.5.7 +.... n terms. Share with your friends Share 1 Shruti Tyagi answered this Dear Student, 11.3+21.3.5+31.3.5.7+....n termsthe given series can be written as∑k=1n k1×3×5×..2k+1⇒12∑k=1n 2×k1×3×5×..2k+1 ----multiply and divide by 2⇒12∑k=1n 2×k+1-11×3×5×..2k+1 ---add and subtract 1⇒12∑k=1n 2×k+11×3×5×..2k+1-∑k=1n 11×3×5×..2k+1⇒12∑k=1n 11×3×5×..2k-1-∑k=1n 11×3×5×..2k+1putting values of k=1 to n, we get series as ⇒1211-11×3+11×3-11×3×5+11×3×5-11×3×5×7+....11×3×5×2n-1-11×3×5×2n+1the terms will get cancelled only the first and last terms remain⇒121-11×3×5×2n+1 Regards, 0 View Full Answer