@vbhvgupta said:-1^2 + 2^2 - 3^2 + 4^2 - 5^2 + 6^2 ... - 17^2 + 18^2 =
=4(1^2+2^2+3^2...+9^2) -(1^2+2^2...+17^2+18^2 -(2^2+4^2...+16^2+18^2)
=8(1^2+...+9^2)-(1^2+2^2...+18^2)
Then solve...phew.
@vbhvgupta said:-1^2 + 2^2 - 3^2 + 4^2 - 5^2 + 6^2 ... - 17^2 + 18^2 =
( 2^2-1^2)+(4^2-3^2)+(6^2-5^2)+.................(18^2-17^2)
3+7+11+.......................+35=(9/2)*(3+35)=171
3+7+11+.......................+35=(9/2)*(3+35)=171
@vbhvgupta said:How many of the following numbers can be expressed as a product of 4 natural numbers in arithmetic progression, of which exactly 3 are in geometric progression? The numbers are 384, 1944, 945, 15000.
945 cannot be expressed
384 = 2*4*6*8
1944 = 3*6*9*12
15000 = 5*10*15*20
But 945 = 3*5*7*9..not possible as it does not satisfy the GP condition
@ankita14 said:Equal ayega :-/ I was confused whether square roots can be negative or not :-/
หลก(x-3) ห = (3-x)
Ha sahi h Equal he ayga. galti se likh diya tha 
Square root k ander square h na to under root m to kabhi -ve to nahi ayga is ques m.
Vaise i (iota) ajate h agar -ve ka under root lenge to.
@AIM_IIM_2013 said:หลก(x-3) ห = (3-x)Ha sahi h Equal he ayga. galti se likh diya tha Square root k ander square h na to under root m to kabhi -ve to nahi ayga is ques m. Vaise i (iota) ajate h agar -ve ka under root lenge to.
Nai mera matlab tha, root of 25, plus minus 5 Hota hai to? Ki sirf +5?
@ankita14 said:Nai mera matlab tha, root of 25, plus minus 5 Hota hai to? Ki sirf +5?
Ha lakin root 25 =+5.to correct he h. Ha -5 bhi hoga.
@ankita14 said:Nai mera matlab tha, root of 25, plus minus 5 Hota hai to? Ki sirf +5?
@AIM_IIM_2013 said:Ha lakin root 25 =+5.to correct he h. Ha -5 bhi hoga.
Root of 25 is +5 only! ;)
@AIM_IIM_2013 said:nahi bro root 25 is both +5 and -5 @falcao
No dude! It's +5 only! and you are talking blunder her ;)
@ScareCrow28 said:No dude! It's +5 only! and you are talking blunder her
Come to a consensus and let me know ๐ :blush:
@ankita14 said:Come to a consensus and let me know
It's +5 and +5 only!!! ๐ -5 is no solution of root 25
Root doesn't give -ve values. Now, here, don't say that (-5)^2 = 25 so root(25) = -5 because by squaring you are adding a root here. If only root 25 is given then it's +5 only!
@AIM_IIM_2013 said:www.calculatorsoup.com/calcula...It is funny.
I told you if the question is a^2 = n (like the one in the link given by you) It will be + and -n.
Because there is a square involved ;)
@AIM_IIM_2013 @ankita14 I will stick to root(25) = +5, no matter what you show to me ๐ 
No offence! :P
@ScareCrow28 : bhai ... i dont know why ... but i think u should write the value instead of comments
i still think that if x^2 = 25 then x= +-5
and same is for under root 25 ...
and for check put value x= -5 and check whether it satisfy or not .. also check whether it is given +ve integers only or not
@ScareCrow28 said:@AIM_IIM_2013@ankita14 I will stick to root(25) = +5, no matter what you show to me No offence!
Mujhe kyu Bol rahe ho, mujhe to doubt that, to clarify kar rahi thi :banghead:
@ziddiarmaan said:@ScareCrow28 : bhai ... i dont know why ... but i think u should write the value instead of comments i still think that if x^2 = 25 then x= +-5and same is for under root 25 ...and for check put value x= -5 and check whether it satisfy or not .. also check whether it is given +ve integers only or not
Dude, As I said, x^2 = 25 has TWO roots. Of course it has -5 as one of the roots.
But, if the question is x = 25, what is Root(x) ??
I suppose you would say it's +5 and -5 and you are wrong here! :)
I think I used values here and not comments...
@ziddiarmaan http://www.mathsisfun.com/algebra/square-root.html
The square roots of 36 are 6 and -6
But์ฐฝหลก36 = 6 (not -6)
But์ฐฝหลก36 = 6 (not -6)