Find for the A.P. (i) (ii) The images show the mathematical expression 'a_30 - a_20', an arithmetic progression '-9, -14, -19, -24,...', and the general form of an arithmetic progression 'a, a + d, a + 2d, a + 3d,...'.

(i)a = -9, d = -14 + 9 = -5a30= a + 29d= -9 + 29(-5) = -154a20= a + 19d= -9 + 19(-5) = -104a30 – a20= -154 – (-104)= -154 + 104= -50(ii)a = a, d = a + d – a = da30= a + 29da20= a+ 19da30 – a20 = a + 29d – a – 19d= 10d

Q20 of 202 Page 9

Findfor the A.P.
(i)

(ii)

(i)

a = -9, d = -14 + 9 = -5

a₃₀= a + 29d

= -9 + 29(-5) = -154

a₂₀= a + 19d

= -9 + 19(-5) = -104

a₃₀ – a₂₀= -154 – (-104)

= -154 + 104

= -50

(ii)

a = a, d = a + d – a = d

a₃₀= a + 29d

a₂₀= a+ 19d

a₃₀ – a₂₀ = a + 29d – a – 19d

= 10d

More from this chapter

All 202 →

The sum of 4^th and 8^th terms of an A.P. is 24 and the sum of the 6^th and 10^th terms is 34. Find the first term and the common difference of the A.P.?

The first term of an A.P. is 5 and its 100^th term is - 292. Find the 50^th term of this A.P.

Write the expressionfor the A.P.