let f(x)= cos([π²]x) + cos([-π²]x) + [e] + [-π],

where [.] is the gretest integer function, then -:

(A) f(π/2) = 5

(B) f(π) = 7

(C) f(-π) = 6

(D) f(π/4) = 8
Ans are option (A) & (C)
but how.? i cant get the approch. how to do it.?

Hello Student, please find the soln
[π²]=9
[-π²]= -10
[e]= 2
[-π]= -4
Now equation becomes
f(x)= cos9x + cos(-10x) + 2 – 4
Now you can check the options.

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