Ch 5 introduces arithmetic progressions — sequences where consecutive terms have a constant difference. Students derive and apply formulas for the nth term and the sum of the first n terms.
An AP is a sequence a, a+d, a+2d, a+3d, … where d is the common difference. d can be positive (increasing), negative (decreasing), or zero (constant). Examples: 2,5,8,11… (d=3); 10,7,4,1,−2… (d=−3).
The nth term aₙ = a + (n−1)d. Sum of first n terms Sₙ = n/2 [2a + (n−1)d] = n/2 (first term + last term). The nth term can also be found as aₙ = Sₙ − Sₙ₋₁.
Download: https://ncert.nic.in/textbook/pdf/jemh105.pdf | Complete book: https://ncert.nic.in/textbook/pdf/jemh1ps.zip
Check if the difference between consecutive terms is constant: a₂−a₁ = a₃−a₂ = a₄−a₃ = … If this common difference is the same throughout, it's an AP.
Book a Trial + Diagnostic session. Get a personalized Learning Path with clear milestones, tutor match, and a plan recommendation — all within 24 hours.
Book Trial + Diagnostic →