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

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

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CENGAGE PUBLICATION-TRIGONOMETRIC FUNCTIONS-All Questions
  1. The most general value for which tantheta=-1 and costheta=1/(sqrt(2)) ...

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

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

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

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

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

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

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

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

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

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  11. Number of solutions of the equation (sqrt(3)+1)^(2x)+(sqrt(3)-1)^(2x)=...

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  12. Prove that cosalpha+cosbeta+cosgamma+cos(alpha+beta+gamma)= 4cos((alph...

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  13. If x=(sin^3P)/cos^2P,y=cos^3P/sin^2P" and " sinP+cosP=1/2 then find th...

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  14. Number of solution(s) of the equation (sinx)/(cos3x)+(sin3x)/(cos9x)+(...

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  15. prove that (sinA+sin3A+sin5A+sin7A)/(cosA+cos3A+cos5A+cos7A)=tan4A

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  16. Prove that (r+r1)tan((B-C)/2)+(r+r2)tan((C-A)/2)+(r+r3)tan((A-B)/2)=0

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  17. (a+2)sinalpha+(2a-1)cosalpha=(2a+1)iftanalpha"i s" (a) 3/4 (b) 4...

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  18. If x , y in [0,2pi]a n dsinx+siny=2, then the value of x+y is

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  19. Find the value of (1+cos (pi/8))(1+cos(3pi/8))(1+cos(5pi/8))(1+cos(7pi...

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  20. Let A B C be a triangle with incentre at I Also, let P and Q be the fe...

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