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if alpha+beta+gamma=2pi prove that cos^2...

if `alpha+beta+gamma=2pi` prove that `cos^2alpha+cos^2beta+cos^2gamma-2cosalphacosbetacosgamma=1`

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PATHFINDER-TRIGONOMETRIC RATIOS AND IDENTITIES-QUESTION BANK
  1. For all theta in [0,pi/2] show that cos(sintheta)gtsin(costheta)

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  2. Show that the value of the function (sinxcos3x)/(cosxsin3x), where eve...

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  3. if alpha+beta+gamma=2pi prove that cos^2alpha+cos^2beta+cos^2gamma-2co...

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  4. If cosalpha+cosbeta=1/3 and sinalpha+sinbeta=1/4 prove that cos(alpha-...

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  5. Find the value of t, where t in [-pi/2,pi/2] so that 2sint=(5x^2-2x+1...

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  6. If exp{(sin^2 x+sin^4 x+sin^6 x+...)In2} satisfies the quadratic equat...

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  7. If A+B+C=180^@ prove that: sin(B+2C)+sin(C+2A)+sin(A+2B)= 4 sin((B-C)/...

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  8. Prove that (1+sec2theta)(1+sec2^2theta)(1+sec2^3theta)…..(1+sec2^nthet...

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  9. If cot(2x/3)+tan(x/3)=cosec(kx)/3 then the value of k is

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  10. যদি thetain(frac[pi][2],frac[3pi][2]) হয়, তবে sqrt(4cos^4theta+sin^2(2...

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  11. Which one of the following statements is correct ?

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  12. For x belongs to (o,pi) the equation sinx+2sin2x-sin3x=3 has

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  13. Let fk(x)=1/k(sin^k x+cos^k x) Then f4(x)-f6(x) =

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  14. The value of tan(pi/3)+2tan((2pi)/3)+4cot((4pi)/3)+8tan((8pi)/3) is

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  15. The sum of the series underset(n=1)sum sin((nipi)/720) is

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  16. The minimum value of 2^(sin x) + 2^(cos x) is

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  17. cos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)

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  18. The expression tanA(1-cotA)+cotA/(1-tanA) can be written as

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  19. For 0leP, Qle(pi/2)if sinP+cosQ=2 then the value of tan((P+Q)/2) is eq...

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  20. Let f(theta)=(1+sin^2 theta)(2-sin^2 theta) then for all values

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