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The period of the function f(x)=cos2p...

The period of the function
`f(x)=cos2pi{2x}+ sin2 pi {2x}`,
is ( where {x} denotes the functional part of x)

A

`1`

B

`(pi)/(2)`

C

`(1)/(2)`

D

`pi`

Text Solution

Verified by Experts

The correct Answer is:
C

We have,
`f(x)=cos2pi{2x}+ sin 2 pi{2x}`
`implies f(x)= cos2pi(2pi-[2x])+ sin2pi (2pi-[2x])`
`implies f(x)=cos(2pi[2x]-4pix)-sin(2pi[2x]-4pix)`
`implies f(x)= cos 4 x + sin 4 pi x " " [{:( :' cos (2npi-theta)= cos theta ),( sin (2n pi-theta)=- sin theta]`
Since ` cos 4 pi x ` and ` sin 4 pi x` are periodic functions each with period`(2pi)/(4pi)=(1)/(2)`.
Therefore, f(x) is periodicc with period `(1)/(2)`.
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OBJECTIVE RD SHARMA ENGLISH-REAL FUNCTIONS -Chapter Test
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  3. The value of integer n for which the function f(x)=(sinx)/(sin(x / n)...

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  4. The period of the function f(x)=sin((2x+3)/(6pi)), is

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  5. The domain of the function f(x)=sqrt(log((1)/(|sinx|)))

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  6. The domain of the function f(x)=log(10) (sqrt(x-4)+sqrt(6-x)) is :

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  7. Let f(x)=(sqrt(sinx))/(1+(sinx)^(1/3)) then domain f contains

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  8. If f : R -> R is defined by f(x) = [2x] - 2[x] for x in R, where [x] i...

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  9. If N denotes the set of all positive integers and if f : N -> N is def...

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  10. The set of value of a for which the function f(x)=sinx+[(x^(2))/(a)] d...

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  11. If f(x)={{:(-1, x lt 0),(0, x=0 and g(x)=x(1-x^(2))", then"),(1, x gt ...

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  12. Find the equivalent definition of f(x)=max.{x^(2),(1-x)^(2),2x(1-x)...

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  13. If f(x) is defined on [0,1], then the domain of f(3x^(2)) , is

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  14. The function f(x) is defined in [0,1] . Find the domain of f(t a nx)do...

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  15. The domain of definition of the real function f(x)=sqrt(log(12)x^(2)) ...

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  16. The values of ba n dc for which the identity of f(x+1)-f(x)=8x+3 is sa...

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  17. The function f(x)=sin""(pix)/(2)+2 cos ""(pix)/(3)-tan""(pix)/(4) is p...

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  18. The period of the function sin""((pix)/(2))+cos((pix)/(2)), is

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  19. If x in R, then f(x)=sin^(-1)((2x)/(1+x^(2))) is equal to

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  20. If x in R , then f(x)=cos^(-1)((1-x^(2))/(1+x^(2))) is equal to

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  21. The equivalent definition of the function f(x)=lim(n to oo)(x^(n)-x^(-...

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