trigno

the number of ordered pairs (a,b) where a,b belongs to (-Ï€,Ï€) satisfying cos (a-b) =1 and cos (a+b) =1/e will be ???????????

12 Answers

1
skygirl ·

cos^-1 (1/e) ka kuchh value diya hai kya ?

1
skygirl ·

simply karlo naa...

a-b = cos^-1 1

a+b = cos^-1 (1/e)

etc. etc.

1
big looser ......... ·

i think e is exponent...
it was asked in jee 2005

1
skygirl ·

[12]

1
skygirl ·

a-b = 0 (a-b cant be taken 2pi ,,,, then a has to greater than 2pi which is not possible)

and a+b = cos^-1 (1/e) and 2pi-cos^-1 (1/e) both

then we get two pairs.

1
mkagenius ·

total 2 ordered pair.......

1
mkagenius ·

samjh mein aaye to bataana......

1
skygirl ·

yeah exactly mkg !

1
mkagenius ·

K

1
big looser ......... ·

but the answer given is 4

1357
Manish Shankar ·

yeah it will be 4

a=b

so cos(2a)=1/e

2a=2nπ±cos-1(1/e)

a=nπ±(1/2)cos-1(1/e)

so a=±(1/2)cos-1(1/e), π-(1/2)cos-1(1/e), -π+(1/2)cos-1(1/e)

1
skygirl ·

[12]

great!

chhhi chhi kaise nahi sochi yeh cheez?? [12]

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