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In a DeltaA B C prove that cos(A+B)+cos...

In a `DeltaA B C` prove that `cos(A+B)+cos C=0.`

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RD SHARMA ENGLISH-TRIGONOMETRIC FUNCTIONS-All Questions
  1. Prove that : tan((11pi)/3)-2sin((9pi)/3)-3/4cosec^2(pi/4)+4cos^2((17pi...

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  2. Prove that: 3sin(pi/6)sec(pi/3)-4sin((5pi)/6)cot(pi/4)=1

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  3. In a DeltaA B C prove that cos(A+B)+cos C=0.

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  4. In a DeltaA B C prove that cos ((A+B)/2)=sin (C/2).

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  5. In a "DeltaA B C prove that tan(("A"+"B")/2)=cot("C"/2)

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  6. If A ,\ B ,\ C ,\ D be the angles of a cyclic quadrilateral, taken in ...

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  7. Find x from the following equation: cos e c(90^0+theta)+x costhetacot(...

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  8. Find x from the following equation: xcot(90^0+theta)+tan(90^0+theta)si...

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  9. Prove that: t a n 720^0-cos 270^0-sin 150^0cos 120^0=1/4

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  10. Prove that: sin 780^0sin 480^0+cos 120^0sin 150^0=1/2

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  11. Prove that: sin780^0sin 120^0+cos 240^0sin390^0=1/2

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  12. Prove that: sin600^0cos 390^0+cos 480^0sin 150^0=-1

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  13. Prove that : tan 225^@ cot 405^@+ tan 765^@ cot 675^@=0

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  14. Write the maximum and minimum values of cos(cosx)

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  15. Write the maximum and minimum values of sinx dot

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  16. Write the maximum value of sin(cosx)dot

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  17. If sin x=cos^2x ,\ then write the value of cos^2x\ (1+cos^2x)dot

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  18. If sin x+cosec\ x=2, then write the value of sin^n x+cos e c^n xdot

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  19. If sintheta1+sintheta2+sintheta3=3, then costheta1+costheta2+costheta3...

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  20. Write the value of sin 10^0+sin 20^0+sin 30^0+....+sin 360^@

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