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Prove that, costhetacos((theta)/(2))-c...

Prove that,
`costhetacos((theta)/(2))-cos3thetacos((9theta)/(2))=sin7thetasin8theta`.

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The correct Answer is:
`sin(8theta).sin(7theta)`
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KUMAR PRAKASHAN-TRIGONOMETRIC FUNCTIONS -SOLUTION OF NCERT EXEMPLAR PROBLEMS (SHORT ANSWER TYPE QUESTIONS)
  1. Prove that (tanA+secA-1)/(tanA-secA+1)=(1+sinA)/(cosA) Thinking Proc...

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  2. If (2sinalpha)/(1+cosalpha+sinalpha)=y, then prove that (1-cosalpha+si...

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  3. If msintheta=nsin(theta+2alpha), then prove that tan(theta+alpha)cotal...

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  4. If cos(alpha+beta)=(4)/(5)andsin(alpha+beta)=(5)/(13), where alpha lie...

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  5. If tanx=(b)/(a), then find the value of sqrt((a+b)/(a-b))+sqrt((a-b)...

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  6. Prove that, costhetacos((theta)/(2))-cos3thetacos((9theta)/(2))=sin7...

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  7. If acostheta+bsintheta=mandasintheta-bcostheta=n, then show that, a^(2...

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  8. Find the value of tan(22^(@)30').

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  9. Prove that, sin4A=4sinAcos^(3)A-4cosAsin^(3)A.

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  10. If tantheta+sintheta=mandtantheta-sintheta=n, then prove that m^(2)-n^...

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  11. If tan(A+B)=p and tan(A-B)=q, then show that tan2A=(p+q)/(1-pq).

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  12. If cosalpha+cosbeta=0=sinalpha+sinbeta, then prove that cos2alpha+cos2...

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  13. If (sin(x+y))/(sin(x-y))=(a+b)/(a-b), then show that (tanx)/(tany)=(a)...

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  14. If tantheta=(sinalpha-cosalpha)/(sinalpha+cosalpha), then show that si...

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  15. If sintheta+costheta=1, then find the general value of theta.

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  16. Find the most general value of theta satisfying the equation tantheta=...

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  17. If cottheta+tantheta=2cosectheta, then find the general value of theta...

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  18. If 2sin^(2)theta=3costheta,"where "0lethetale2pi, then find the value ...

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  19. If secxcos5x+1=0,"where "0ltxle(pi)/(2), then find the value of x.

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