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Prove that (cosalpha+cosbeta)^2+(sinalph...

Prove that `(cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-beta)/2)dot`

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CENGAGE PUBLICATION-TRIGONOMETRIC FUNCTIONS-All Questions
  1. If r1 =r2+r3+r, prove that the triangle is right angled.

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  2. Find the number of solution of theta in [0,2pi] satisfying the equati...

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  3. Prove that (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-bet...

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  4. Let A=sinx+cosxdot Then find the value of sin^4x+cos^4x in terms of Ad...

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  5. ABC is an acute angled triangle with circumcenter O and orthocentre H....

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  6. If sintheta=1/2a n dcostheta=-(sqrt(3))/2, then the general value of t...

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  7. In quadrilateral A B C D , if sin((A+B)/2)cos((A-B)/2)+"sin"((C+D)/2)c...

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  8. Find the range of y=sin^3x-6sin^2x+11sinx-6.

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  9. A ladder rest against a wall making an angle alpha with the horizontal...

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  10. Let ABC be an acute angled triangle whose orthocentre is at H. If a...

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  11. The most general value for which tantheta=-1 and costheta=1/(sqrt(2)) ...

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  12. The equation sin^2theta=(x^2+y^2)/(2x y),x , y!=0 is possible if

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  13. Prove that: cos18^0-sin18^0 = sqrt(2)sin27^0

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  14. In a acute angled triangle ABC, proint D, E and F are the feet of the ...

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  15. The number of solutions of the equation cos^2(x+pi/6)+cos^2x-2cos(x+pi...

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  16. Which of the following is correct ? (a) sin1^@>sin1(b) sin1>sin1^@ (c)...

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  17. Prove that: (sin5A-sin3A)/(cos5A+cos3A)=tanA

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  18. For triangle ABC,R=5/2 and r=1. Let I be the incenter of the triangle ...

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  19. If 5tantheta=4, then (5sintheta-3costheta)/(5sintheta+2costheta) is eq...

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  20. Prove that (r1+r2)/(1+cosC)=2R

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