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If vec alpha, vec beta, vecgamma be thre...

If `vec alpha, vec beta, vecgamma` be three unit vectors such that `|vec alpha+vec beta+vec gamma|=1` and `vec alpha` is perpendicular to `vec beta` while `vec gamma` makes angles `theta` and `phi` with `vec alpha` and `vec beta` respectively, then the value of `cos theta+cos phi` is -

A

`(5)/(4)`

B

`-(5)/(4)`

C

1

D

-1

Text Solution

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The correct Answer is:
D
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CHHAYA PUBLICATION-MCQ ZONE -Question Paper 3
  1. If veca=2hati-5hatj+4hatk and vecb=hati-4hatj+6hatk, then a unit v...

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  2. If veca+vecb+vec c=vec0 and |veca|=3,|vecb|=5 and |vec c|=7, then the ...

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  3. If vec alpha, vec beta, vecgamma be three unit vectors such that |ve...

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  4. If veca=2hati+5hatj+7hatk and vecb=hati-hatj+5hatk, then the vecor co...

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  5. The image of the point (-3, 5, 2) in the plane 2x-y+z+3=0 is -

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  6. The equation of the plane passing through the points (1, -1, 2) and (2...

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  7. The values of x, at which the first derivative of the function (x+(1)...

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  8. If f(x)=sin3x cos4x, then the value of f''((pi)/(2)) is -

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  9. Let f(x) be a differentiable even function, consider the following sta...

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  10. If y=x+x^(2)+x^(3)+…oo where |x| lt 1, then for |y| lt 1 the value of...

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  11. Find which function does not obey mean value theorem in [0, 1] -

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  12. The derivative of sec^(-1)((1)/(2x^(2)-1))" w.r.t. "sqrt(1-x^(2)) " at...

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  13. The derivative of the function f(x)=log(5)(log(7)x)[x gt 7] is -

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  14. If 2y=(x-a)sqrt(2ax-x^(2))+a^(2)"sin"^(-1)(x-a)/(a), then the value of...

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  15. The value of lim(x to 0)(1+3x)^((x+2)/(x)) is -

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  16. If y=x^(3) then the value of ((d^(2)y)/(dx^(2)))/([1+((dy)/(dx))^(2)]^...

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  17. If x=(1)/(z), y=f(x) and (d^(2)y)/(dx^(2))=kz^(3)(dy)/(dz)+z^(4)(d^(2...

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  18. If xy=ax^(2)+(b)/(x), then the value of x^(2)(d^(2)y)/(dx^(2))+2x(dy...

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  19. The value of c in Rolle's theorem when f(x)=2x^(3)-5x^(2)-4x+3, x in [...

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  20. Let f(x)={((sin pix)/(5x),"when "x ne 0),(k,"when "x=0):} If f(x) i...

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