# Unit 04: Sequences and Seeries

This is a forth unit of the book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. On this page we have provided the solutions of the questions.

After reading this unit the students will be able to

- Define an arithmetic sequence and find its general term.
- Know arithmetic means between two numbers. Also insert $n$ arithmetic means between them.
- Define an arithmetic series and establish the formula to find the sum of $n$ terms of the series.
- Show that sum of $n$ arithmatic means between two numbers is equal to $n$ times their A.M.
- Solve real life problems involving arithmetic sequence, arithmetic means and arithmetic series.
- Define a geometric sequence and its general term.
- Know geometric means between two numbers, Also insert $n$ geometric means between them.
- Define geometric series and find the sum of $n$ terms of a geometric series.
- Find the sum of an infinite geometric series.
- Convert the recurring decimial into an equivalent common fracion.
- Define arithmetic geometric series.
- Find the sum of $n$ terms of the arithmetico-geometric series.