(iii) a2 + b2, ab + bc, b2 + c2 Solution: (iii) a2 + b2, ab + bc, b2 + c2 According to the question, a, b, c are in GP. Making use of the property of geometric mean, b2 = ac a2 + b2, ab + bc, b2 +...
If a, b, c are in G.P., prove that the following are also in G.P.:
(i) a2, b2, c2 (ii) a3, b3, c3 Solution: (i) a2, b2, c2 According to the question, a, b, c are in GP. Making use of the property of geometric mean, we can write: b2 = ac Upon squaring both the sides...
If a, b, c, d are in G.P., prove that:
(iii) (b + c) (b + d) = (c + a) (c + d) Solution: (iii) (b + c) (b + d) = (c + a) (c + d) According to the question, a, b, c are in GP. Making use of the property of geometric mean, we can write:...
If a, b, c, d are in G.P., prove that:
(i) (ab – cd) / (b2 – c2) = (a + c) / b (ii) (a + b + c + d)2 = (a + b)2 + 2(b + c)2 + (c + d)2 Solution: (i) (ab – cd) / (b2 – c2) = (a + c) / b According to the question a, b, c are in GP. Making...
if a, b, c are in G.P., prove that:
(v) (a + 2b + 2c) (a – 2b + 2c) = a2 + 4c2 Solution: (v) (a + 2b + 2c) (a – 2b + 2c) = a2 + 4c2 According to the question, a, b, c are in GP. Making use of the property of geometric mean, b2 = ac...
if a, b, c are in G.P., prove that:
(iii) (a+b+c)2 / (a2 + b2 + c2) = (a+b+c) / (a-b+c) (iv) 1/(a2 – b2) + 1/b2 = 1/(b2 – c2) Solution: (iii) (a+b+c)2 / (a2 + b2 + c2) = (a+b+c) / (a-b+c) According to the question, a, b, c are in GP....
if a, b, c are in G.P., prove that:
(i) a(b2 + c2) = c(a2 + b2) (ii) a2b2c2 [1/a3 + 1/b3 + 1/c3] = a3 + b3 + c3 Solution: (i) a(b2 + c2) = c(a2 + b2) According to the question, a, b, c are in GP. Making use of the property of...
The sum of three numbers in G.P. is 56. If we subtract 1, 7, 21 from these numbers in that order, we obtain an A.P. Find the numbers.
Solution: Suppose that the three numbers are a, ar, ar2 According to the question statement, a + ar + ar2 = 56 … (1) subtracting 1,7,21 respectively from these terms,we get: (a – 1), (ar – 7),...
The sum of three numbers a, b, c in A.P. is 18. If a and b are each increased by 4 and c is increased by 36, the new numbers form a G.P. Find a, b, c.
Solution: Consider the first term of an A.P. to be ‘a’ and let its common difference be given by ‘d’. Therefore, we can write: b = a + d and c = a + 2d. It is gien that: a + b + c = 18 Or, we can...
The sum of three numbers which are consecutive terms of an A.P. is 21. If the second number is reduced by 1 and the third is increased by 1, we obtain three consecutive terms of a G.P. Find the numbers.
Solution: Consider the first term of an A.P. to be ‘a’ and let its common difference be‘d’. Therefore, we can write: a1 + a2 + a3 = 21 Where the three numbers are as follows: a, a + d, and a + 2d...
Three numbers are in A.P., and their sum is 15. If 1, 3, 9 be added to them respectively, they from a G.P. find the numbers.
Solution: Consider the first term of an A.P. to be ‘a’ and let its common difference be‘d’. We have, a1 + a2 + a3 = 15 Where the three numbers are as follows: a, a + d, and a + 2d So, we can write:...
Find k such that k + 9, k – 6 and 4 form three consecutive terms of a G.P.
Solution: Suppose that a = k + 9; b = k−6; and c = 4; According to the question, a, b and c are in GP, then Making use of the property of geometric mean, we get: b2 = ac $ {{\left( k-6...
If a, b, c are in G.P., prove that 1/loga m , 1/logb m, 1/logc m are in A.P.
Solution: According to the question, a, b and c are in GP Making use of the property of geometric mean, we can write: b2 = ac Taking log on both sides with base m, we get: $...
If a, b, c are in G.P., prove that log a, log b, log c are in A.P.
Solution: According to the question, a, b and c are in G.P. By making use of the property of Geometric mean, we can write: $ {{b}^{2}}=~ac $ $ ~{{\left( {{b}^{2}} \right)}^{n}}~=~{{\left( ac...