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If 1/a,1/b,1/c are in A.P and a,b -2c, a...

If `1/a,1/b,1/c` are in A.P and a,b -2c, are in G.P where a,b,c are non-zero then

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The correct Answer is:
A, B, C, D

we have `b=(2ac)/(a+c)` and `b^(2)=-2ac`
`thereforeb=(-b^(2))/(a+c)`
`rArr a+b+c=0`
`rArr2b-2a-2c`
Therefore, -2a,b,-2c are in A.P.
Also, `a^(3)+b^(3)+c^(3)=3abc`
Since `b^(2)=-2ac,b^(4)=4a^(2)c^(2)`
So, `a^(2),b^(2),4c^(2)` are in G.P.
Since a+b+c=0, equations `ax^(2)+bx+c=0` has one root x=1
So, equation has real roots.
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CENGAGE-PROGRESSION AND SERIES-Exercise (Multiple & Comprehension)
  1. The numbers 1, 4, 16 can be three terms (not necessarily consecutive) ...

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  2. The sum of an infinite geometric series is 162 and the sum of its firs...

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  3. If 1/a,1/b,1/c are in A.P and a,b -2c, are in G.P where a,b,c are non-...

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  4. Sum of an infinite G.P is 2 and sum of its two terms is 1.If its secon...

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  5. For 0 lt phi lt pi//2 , if x =Sigma(n=0)^(oo) cos^(2n) phi ,y=Sigma(n...

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  6. For the series, S=1 +(1)/(1+3)(1+2)^2+(1)/((1+3+5))(1+2+3)^2+(1)/((1...

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  7. If Sigma(r=1)^(n) r(r+1)(2r +3)=an^4+bn^3+cn^2+dn +e then

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  8. If Sn=1^2-2^2+3^2-4^2+5^2-6^2+ ,t h e n S(40)=-820 b. S(2n)> S(2n+2) ...

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  9. 1/(sqrt(2)+sqrt(5))+1/(sqrt(5)+sqrt(8))+1/(sqrt(8)+sqrt(11))+ n terms ...

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  10. Given that x+y+z =15 when a,x,y,z,b are in A.P and 1/x+1/y+1/z=5/3 whe...

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  11. If a, b and c are in H.P., then the value of ((ac+ab-bc)(ab+bc-ac))/(a...

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  12. If p,q and r are in A.P then which of the following is / are true ?

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  13. If x^2+9y^2+25 z^2=x y z((15)/2+5/y+3/z),t h e n x ,y ,a n dz are in ...

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  14. If A1, A2, G1, G2, ; a n dH1, H2 are two arithmetic, geometric and har...

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  15. If 1/(b-a)+1/(b-c)=1/a+1/c , then a ,b ,a n dc are in H.P. a ,b ,a n d...

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  16. If a,b,c are three distinct numbers in G.P., b,c,a are in A.P and a,bc...

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  17. If a,b,c are in A.P and a^2,b^2,c^2 are in H.P then which is of the fo...

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  18. If first and (2n-1)^(th) terms of A.P., G.P. and H.P. are equal and th...

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  19. Let E=1/(1^2)+1/(2^2)+1/(3^2)+ Then, E<3 b. E >3//2 c. E >2 d. E<2

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  20. Sum of certain consecutive odd positive intergers is 57^2 -13^2 The l...

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