6. Ifa, a are in A.P., then azn - a, a,+2 - an +...+ is...

Transcribed Image Text:

6. ינ Ifa, a are in A.P., then azn - a, a,+2 - an +...+ is equal to azn+1 + a, az, + az an+2 +a, n(n+1) a2 - a п(n +1) b. а. с. (п + 1) (а, — ,) d. none of these 6.ANS:A 7. V Edit with WPS Office Scanned with CamScanner Given that x + y + z = 15 when a, x, y, z, b are in A.P. and 1. 1 1 5 when a, x, y, z, b are in H.P. Then -+-+-= y a. G.M. of a and b is 3 3 b. one possible value of a + 2b is 11 c. A.M. of a and b is 6 d. greatest value of a- b is 8 7.ANS:ABD 8. If a, b, and c are in H.P. then the valuc of (ac + ab - bc) (ab + bc - ac) is (abc)? (a +c) (3a -c) a. 4a?c? b. bc 62 (а - с) (За + с) d. с. bc a? 4a?c? 8.ANS:AB 9. 15 If x? + 9y? + 25z2 = xyz 3 then x, Y +-+- y and z are in (A) AGP (B) GP (C) AP (D) HP 9.ANS:D 10. be in A.P. and h,, h,. h, be in H.P. If Let a,, a, a, = h, = 2 and a = h = 3, then a h, is ..., 10 %3D 10 а. 2 b. 3 с. 5 d. 6 (IIT-JEE, 1999) 10.ANS:D 6. ינ Ifa, a are in A.P., then azn - a, a,+2 - an +...+ is equal to azn+1 + a, az, + az an+2 +a, n(n+1) a2 - a п(n +1) b. а. с. (п + 1) (а, — ,) d. none of these 6.ANS:A 7. V Edit with WPS Office Scanned with CamScanner Given that x + y + z = 15 when a, x, y, z, b are in A.P. and 1. 1 1 5 when a, x, y, z, b are in H.P. Then -+-+-= y a. G.M. of a and b is 3 3 b. one possible value of a + 2b is 11 c. A.M. of a and b is 6 d. greatest value of a- b is 8 7.ANS:ABD 8. If a, b, and c are in H.P. then the valuc of (ac + ab - bc) (ab + bc - ac) is (abc)? (a +c) (3a -c) a. 4a?c? b. bc 62 (а - с) (За + с) d. с. bc a? 4a?c? 8.ANS:AB 9. 15 If x? + 9y? + 25z2 = xyz 3 then x, Y +-+- y and z are in (A) AGP (B) GP (C) AP (D) HP 9.ANS:D 10. be in A.P. and h,, h,. h, be in H.P. If Let a,, a, a, = h, = 2 and a = h = 3, then a h, is ..., 10 %3D 10 а. 2 b. 3 с. 5 d. 6 (IIT-JEE, 1999) 10.ANS:D