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If f(x)=(cosx+isinx)(cos3x+isin3x)...(co...

If `f(x)=(cosx+isinx)(cos3x+isin3x)...(cos(2n-1)x+isin(2n-1)x)` then `f"(x)` is

A

`n^2y`

B

`-n^4y`

C

`-n^2y`

D

`n^4y`

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The correct Answer is:
B
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TARGET PUBLICATION-DIFFERENTIATION -EVALUATION TEST
  1. If f(x) = (x - 1)/(4) + ((x - 1)^(2))/(12) + ((x -1)^(5))/(20) + ((x -...

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  2. If f(x)=(cosx+isinx)(cos3x+isin3x)...(cos(2n-1)x+isin(2n-1)x) then f"(...

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  3. If y=f((3x+pi)/(5x+4)) and f'(x)=tan^2 x, then (dy)/(dx) at x=0 is

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  4. If y=|cosx|+|sinx|, then (dy)/(dx)" at "x=(2pi)/(3) is

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  5. If y = (1 + (2)/(x)) (1 + (2)/(x))(1 + (3)/(x))...(1 + (n)/(x)) x ...

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  6. If f(x)=x/(1+|x|) for x in R, then f'(0) =

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  7. If y=f((2x+3)/(3-2x)) and f(x)=sin(logx), then (dy)/(dx)=

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  8. d/(dx)[atan^(-1)x+blog((x-1)/(x+1))]=1/(x^4-1)=>a-2b=

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

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  10. If d/(dx)((1+x^4+x^8)/(1+x^2+x^4))=ax^3+bx,then

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  11. If 2x=y^(1/5)+y^(-1/5) then (x^2-1)(d^2y)/dx^2+xdy/dx=ky , then find t...

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  12. if sqrt(x^2+y^2)=ae^(tan^-1 (y/x)) , a > 0, (y(0) > 0) then y"(0) equa...

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  13. If f(x), g(x), h(x) are polynomials in x of degree 2 If F(x)=|[f,g,h],...

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  14. If y= cos ax and yn is n^(th) derivative of y, then |{:(y,y1,y2),(y3...

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  15. If y = sin[cos^(-1){sin(cos^(-1) x)}], "then" (dy)/(dx)" at x" = (1)/...

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  16. If 8f(x)+6f(1/x)=x+5 and y=x^2(f(x), then (dy)/(dx) at x=-1 is equal t...

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  17. If the function f defined on R-{0} os a dIfferentiable function and f(...

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  18. If the function f(x)=x^(3)+e^(x//2)andg(x)=f^(-1)(x), then the value ...

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  19. If y=f(x^3),z=g(x^5),f'(x)=tanx and g'(x)=sec x, then (dy)/(dz)=

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  20. If sqrt(1-x^6)+sqrt(1-y^6)=a(x^3-y^3),p rov et h a t(dy)/(dx)=(x^2)/(y...

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