@sampras said:given : x=(rt3+1)/2 ...... 2x-1 = rt3 ..... squaring... 2x^2-2x-1 = 0now given eqn ... 4x^3+2x^2-8x+7 = (2x^2-2x-1)(2x+3) + 10 = 10 ..... Ans
@Brooklyn said: @sampras : yar mera to written hua den GD tha usi mei lag gyi ....
@sampras said: @pathakrahul Dr sahab kaha ho chhup chhup ke like pe click kar rahe ho...good morning
@pathakrahul said:nahi bhai abhi aaya hun aapka diya hua soln dekh raha tha.thanks aapne qn ka soln de diya....i was trying but could not be able to evaluate........ thanks again
@Brooklyn said:@sampras : CGLE nikal lu kafi hailife mei aaram bhi bura nhi hota
If X^a.x^b.x^c = 1 then the value of a^3 + b^3 + c^3
is
(A) 9 (B) abc
(C) a + b + c (D) 3abc
If a^2 + b^2 + c^2 = 2(a – b – c) – 3, then the
value of (a – b + c) is
(A) -1 (B) 3
(C) 1 (D) -2
bit confused abt method....please post something abt method...
@sampras said: @abhi_1234Q. when (67^67 +67) is divided by 68 the remainder is ...please explain the logic and method involved .... as confused in Binomial expansion...
on dividing
we can write as [(68-1)^67]/68 + 67/68
first part we get remainder -1 second part 67(still process is not completed)
finally (-1 + 67)/68 remainder is 66
@JS-M said:thanx........yr 1 query solve to karo..........like 2x^2-2x-1 = 0, if find the D and roots then x will be (rt3+1)/2 and (rt3-1)/2then if we take thz equation as2x(x-1) = 1 and then x = 1/2 and 3/2so what i have done wrong in latter case nd i knw that it z wrong smwhr..plz explain..
@abhi_1234 said:(67^67 + 67)= [(68 - 1)^67 + 67] on dividing we can write as [(68-1)^67]/68 + 67/68 first part we get remainder -1 second part 67(still process is not completed) finally (-1 + 67)/68 remainder is 66
@NailedNCrushed said:If X^a.x^b.x^c = 1 then the value of a^3 + b^3 + c^3
is
(A) 9 (B) abc
(C) a + b + c (D) 3abc
If a^2 + b^2 + c^2 = 2(a – b – c) – 3, then the
value of (a – b + c) is
(A) -1 (B) 3
(C) 1 (D) -2
bit confused abt method....please post something abt method...
@ lalit5800 and sumit1234567890 u both are correct ...but can you tell me what is the trick to solve it????
@NailedNCrushed said:If X^a.x^b.x^c = 1 then the value of a^3 + b^3 + c^3
is
(A) 9 (B) abc
(C) a + b + c (D) 3abc
If a^2 + b^2 + c^2 = 2(a – b – c) – 3, then the
value of (a – b + c) is
(A) -1 (B) 3
(C) 1 (D) -2
bit confused abt method....please post something abt method...
Guys i have not received my CGL admit card so can i take the printout in exam?????
x=(rt3 + 1)/2 and x-1= (rt3 - 1)/2 ,therefore x(x-1)= 1/2 ....eq1
(2x-1)^2=3 => 2x^2 -2x-1=0 => 2x^2=2x+1....eq.2
Now 4x^3+2x^2 - 8x + 7= 2x(2x^2+x-4) + 7
put 2x^2 value from 2 here
2x(3x-3) + 7 = 6x(x-1) + 7 substitute x(x-1) from 1 and get answr...
@sampras said:Q. if x = (root3 + 1)/2 then 4x^3+2x^2 - 8x + 7 is....
1.x^a*x^b*x^c=1 => x^(a+b+c)=1
So there is only 1 possibilty when x^(a+b+c)=1 i.e a+b+c=0
Now if a+b+c=0
a^3+b^3+c^3=3abc.........its a standard result u can memorise it
2.
a^2 + b^2 + c^2 = 2(a – b – c) – 3
=> a^2 + b^2 + c^2-2a+2b+2c+3=0
=> (a^2-2a+1)+(b^2+2b+1)+(c^2+2c+1)=0
Now the term in bracket can be converted to whole squares as follows
(a-1)^2+(b+1)^2+(c+1)^2=0
Now since we have square term in the expression so for the expression
to be 0 all the term should be seperately equal to 0
i.e. a-1=0,b+1=0,c+1=0
=> a=1,b= -1,c=-1
so a-b+c=1 and hence the ans
@NailedNCrushed said:If X^a.x^b.x^c = 1 then the value of a^3 + b^3 + c^3
is
(A) 9 (B) abc
(C) a + b + c (D) 3abc
If a^2 + b^2 + c^2 = 2(a – b – c) – 3, then the
value of (a – b + c) is
(A) -1 (B) 3
(C) 1 (D) -2
bit confused abt method....please post something abt method...