FunctionHard
Question
If f(x) = cos(ln x), then f(x) f(y) -
has the value
has the valueOptions
A.-1
B.1/2
C.-2
D.None of these
Solution
f(x) = cos (ln x)
f(x) . f(y) = cos(ln x) . cos (ln y)
f (x/y) + f(xy) = cos (ln x - lny) + cos (ln x + ln y)
∴ f(x) . f(y) -
= cos (ln x) cos (ln y) - 
[2 cos(lnx) cos (ln y) = 0
f(x) . f(y) = cos(ln x) . cos (ln y)
f (x/y) + f(xy) = cos (ln x - lny) + cos (ln x + ln y)
∴ f(x) . f(y) -
= cos (ln x) cos (ln y) - [2 cos(lnx) cos (ln y) = 0Create a free account to view solution
View Solution FreeMore Function Questions
The greatest value of the function f (x) = (sin-1 x)3 + (cos-1 x)3 is:...If f : R → R, f(x) = x2, then {x| f (x) = −1} equals-...If x2 + 6x − 27 > 0 and x2 − 3x − 4 < 0, then-...Which of the following functions are aperiodic (where [.] denotes greatest integer function)...Function f : R, f(x) = tan x is...