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If f(x) = cos x cos 2x cos 4x cos (8x). ...

If `f(x) = cos x cos 2x cos 4x cos (8x). cos 16x` then find `f' (pi/4)`

A

`sqrt2`

B

`1/(sqrt2) `

C

1

D

`-1`

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A
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If f(x)=cos x cos2x cos4x cos(8x)*cos16x then find f'((pi)/(4))

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AAKASH INSTITUTE-CONTINUITY AND DIFFERENTIABILITY-Assignment ( section -A)
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  2. If y=(1+x)(1+x^2)(1+x^4)(1+x^(2n)), then find (dy)/(dx)a tx=0.

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  3. If f(x) = cos x cos 2x cos 4x cos (8x). cos 16x then find f' (pi/4)

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  4. If y = cos^(-1)(cos x) then dy/dx at x = (5pi)/4 is (i)1 (ii)-1 (ii...

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  6. if x^y . y^x =16 then dy/dx at (2,2) is equal to

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  8. Let the function y = f(x) be given by x= t^(5) -5t^(3) -20t +7 ...

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  9. If u=f(x^3),v=g(x^2),f^(prime)(x)=cosx ,a n dg^(prime)(x)=sinx ,t h e ...

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  15. If x=2a t , y=a t^2 , where a is a constant, then find (d^2y)/(dx^2...

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  16. If y = x^(1/x) , the value of (dy)/(dx) at x =e is equal to

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  17. If y = tan^(1-) sqrt((x+1)/(x-1)) " for " |x| gt 1 " then " (dy)/(dx)...

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  18. If y="log"(2)"log"(2)(x), then (dy)/(dx) is equal to

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  19. if f'(x)=sqrt(2x^2-1) and y=f(x^2) then (dy)/(dx) at x=1 is:

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  20. Let the function f(x) be defined as f(x) = {:{((logx-1)/(x-e) , xnee),...

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