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Prove that cos 24^(@)+cos 55^(@)+cos 125...

Prove that `cos 24^(@)+cos 55^(@)+cos 125^(@)+cos 204^(@)+cos 300^(@)=1/2`

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The correct Answer is:
`cos 60^(@)=1/2`
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FULL MARKS-TRIGONOMETRY-Additional Questions Solved
  1. Prove that sin 600^(@)* tan (-690^(@))+sec 840^(@)*cot(-945^(@))=3/2

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  2. Prove that sin (270^(@)-theta) sin (90^(@)-theta)-cos(270^(@)-theta) c...

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  3. Prove that cos 24^(@)+cos 55^(@)+cos 125^(@)+cos 204^(@)+cos 300^(@)=1...

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  4. Prove that cos^(2)""pi/8+cos^(2) ""(3pi)/(8)+cos^(2)""(5pi)/(8)+cos^(2...

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  5. Prove that [1+cot alpha-sec(alpha+pi/2)] [1+cot alpha+sec (alpha+pi/2)...

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  6. Write the general form for tantheta

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  7. Simplify (cos(90^@+theta)sec (-theta)tan(180^(@)-theta))/(sec(360^(@)-...

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  8. Find x from the equation cosec (90^(@)+A)+x cos A cot (90^(@)+A)=sin(9...

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  9. Prove that sin (A+B) sin (A-B)=cos^(2) B-cos^(2) A

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  10. Prove that (i) sin A+sin (120^(@)+A)+sin(240^(@)+A)=0 (ii) cos A+c...

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  11. If tan A=5/6, tan B=1/11," show that A+B=45"^(@).

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  12. If A+B=45^(@)," show that "(1+tan A) (1+tan B)=2 and hence deduce the ...

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  13. If tanalpha=1/3,tanbeta=1/7,show that 2alpha +beta=pi/4

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  14. If 2 cos theta=x+1/x then prove that cos 2 theta=1/2 (x^(2)+1/x^(2))

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  15. Prove that cos 20^(@) cos 40^(@) cos 80^(@)=1/8

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  16. Show that 4 sin A sin (60^(@)+A). Sin (60^(@)-A) =sin 3A

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  17. Prove that cos 20^(@) cos 40^(@) cos 80^(@)=1/8

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  18. Prove that sin 20^(@) sin 40^(@) sin 60^(@) sin 80^(@)=3/(16).

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  19. Prove that sin 50^(@)-sin 70^(@)+cos 80^(@)=0.

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  20. Prove that (cos alpha+cos beta)^(2)+(sin alpha -sin beta)^(2)=4 cos^(2...

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