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Prove that 2cos(pi/13)cos((9pi)/13)+cos(...

Prove that `2cos(pi/13)cos((9pi)/13)+cos((3pi)/13)+cos((5pi)/13)=0`

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A N EXCEL PUBLICATION-TRIGONOMETRIC FUNCTIONS-QUESTION BANK
  1. Consider the trignometric equation 4cos^2theta+6sin^2theta=5 prove tha...

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  2. Consider the trignometric equation 4cos^2theta+6sin^2theta=5 prove tha...

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  3. Consider the equation sintheta+sin3theta+sin5theta=0 prove that sin3th...

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  4. Consider the equation sintheta+sin3theta+sin5theta=0 prove that the ge...

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  5. Consider the equation costheta+sintheta=sqrt2 prove that sin((pi/4)+...

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  6. Consider the equation costheta+sintheta=sqrt2 prove that general sol...

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  7. Consider the equation sqrt3sinx-cosx=sqrt2 prove that sin (x-(pi/6)...

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  8. Consider the equation sqrt3sinx-cosx=sqrt2 Prove that the general so...

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  9. Consider the equation tantheta+sectheta=sqrt3 prove that tan((pi/4)...

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  10. Consider the equation tantheta+sectheta=sqrt3 prove that the general...

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  11. Prove that 2cos(pi/13)cos((9pi)/13)+cos((3pi)/13)+cos((5pi)/13)=0

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  12. Prove that (sin3x+sinx)sinx+(cos3x-cosx)cosx=0

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  13. Prove that (cosx+cosy)^2+(sinx-siny)^2=4cos^2((x+y)/2)

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  14. Prove that (cosA-cosB)^2+(sinA-sinB)^2=4sin^2((A-B)/2)

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  15. Prove that sinx+sin3x+sin5x+sin7x=4cosxcos2xsin4x

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  16. Prove that ((sin7x+sin5x)+(sin9x+sin3x))/((cos7x+cos5x)+(cos9x+cos3x))...

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  17. Prove that sin3x+sin2x-sinx=4sinxcos(x/2)cos((3x)/2)

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  18. Find sin(x/2) , cos(x/2) , and tan(x/2) if tanx=-4/3 and x is in the s...

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  19. Find sin(x/2) , cos(x/2) and tan(x/2) if cosx=(-1/3) and x lies in the...

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  20. Find sin(x/2), cos(x/2) and tan(x/2) if sinx=1/4 and x lies in the sec...

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