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

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

A

`sqrt2`

B

`1/(sqrt2) `

C

1

D

`-1`

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AAKASH INSTITUTE ENGLISH-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 cdot cos 2x cdot cos 4x cdot cos 8x cdot cos 16x," the...

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  4. If y=cos^(-1)(cosx),then (dy)/(dx) at x=(5pi)/4 is equal to (a)1 (b)-...

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  5. If x=e^(y+e^(y+e^(y+...oo))),xgt0, then (dy)/(dx) is equal to

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

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  7. If y = sin x^(@) " and " u = cos x " then " (dy)/(du) 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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  10. Find the derivative of sec^(-1)((1)/(2x^(2)-1))" w.r.t. "sqrt(1-x^(2))...

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  11. If t(1+x^(2))=x and x^(2)+t^(2)=y then at x = 2, the value of (dy)/(dx...

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  12. If x=tcost ,y=t+sint . Then (d^2 x)/(dy^2)at t=pi/2 is (a)(pi+4)/2...

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  13. if y = sin 2x , " then " (d^(6)y)/(dx^(6)) " at" x = pi/2 is equal t...

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  14. Let f(x)=|[x^3,sinx,cosx],[6,-1, 0],[p, p^2,p^3]|, where p is a cons...

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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)/(d...

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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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