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Geometric Progression(GP): Formulae based
Example 4
Ex 8.2, 1
Example 5 Important
Ex 8.2, 5 (a)
Ex 8.2, 2
Example 6
Ex 8.2, 4
Ex 8.2, 3 Important
Ex 8.2, 17 Important You are here
Example 7 Important
Ex 8.2, 7 Important
Ex 8.2, 10
Ex 8.2, 9 Important
Ex 8.2, 11 Important
Ex 8.2, 8
Ex 8.2, 19
Ex 8.2, 20
Example 8
Ex 8.2, 13
Ex 8.2, 15
Ex 8.2, 16 Important
Ex 8.2, 21
Ex 8.2, 14 Important
Misc 3
Misc 2
Example 9 Important
Ex 8.2, 12
Example 10 Important
Ex 8.2, 18 Important
Misc 11 (i) Important
Misc 5
Misc 1 Important
Geometric Progression(GP): Formulae based
Last updated at May 29, 2023 by Teachoo
Ex 8.2, 17 If the 4th, 10th and 16th terms of a G.P. are x, y and z, respectively. Prove that x, y, z are in G.P. We know that an = arn 1 where an = nth term of GP n is the number of terms a is the first term r is the common ratio Here, 4th term is x i.e. a4 = x Putting n = 4 in an formula x = ar4 1 x = ar3 Also, 10th term is y i.e. a10 = y Putting n = 10 in an formula y = ar10 1 y = ar9 Also, 16th term is z i.e. a16 = z Putting n = 16 in an formula z = ar16 1 z = ar15 We need to show x, y, z are in GP i.e. we need to show / = / Calculating / / Putting y = ar9 & x = ar3 = 9/ 3 = r9 3 = r6 Now calculating / / putting z = ar15 & y = ar9 = 15/ 9 = r15 9 = r6 Thus, / = r6 , & / = r6 Hence / = / x, y, z are in G.P Hence proved