Ask iit jee aieee pet cbse icse state board community Discussion Response Post to: An interesting one...
Forum Index -> Differential Calculus -> View Full Question Email  
Author Message
Ankit Rana (936)

Blazing goIITian


Ankit Rana's Avatar

total posts: 461    
Offline

 given that  f(x) . f[f(x] = 1

and f(1000) = 999

hence for x = 1000 we have f(1000) . f [ f(1000) ] = 1 

i.e. f(1000) f(999) = 1

hence f (999) = 1/f(1000) = 1/999

now since f is a continous function

it must attain all values between 1/999 and 999 in the interval [999,1000] since f(999) = 1/999 and f(1000) = 999

hence for some x between 999 and 1000 the function will attain 500 such that f(x) = 500

hence we have for that x    f(x) . f[ f(x)] = 500 f(500) = 1

hence f(500) = 1/500

here u need not know the function but u can definitely say that f(500) = 1/500 since we are using the property of continous functions.

0 people liked this
 
Free Sign Up!

Preparing for IIT-JEE ?

Arihant Revision Package for IIT JEE - Books, Practice Tests + Rank Predictor


@ INR 1,995/-

For Quick Info

Name

Mobile No.

Sponsored Ads