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If A=30^@ verify that cos3A=4cos^3A-3cos...

If `A=30^@` verify that `cos3A=4cos^3A-3cosA`

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If secA=5/4 , verify that (3sinA-4sin^3A)/(4cos^3A-3cosA)=(3tanA-tan^3A)/(1-3tan^2A)

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If A=30^(@) , show that : 4cosAcos(60^(@)-A)*cos(60^(@)+A)=cos3A

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RD SHARMA ENGLISH-TRIGONOMETRIC RATIOS-All Questions
  1. Solve each of the following equations when 0 < theta<90 (i) 2sin^2t...

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  2. Find the value of theta in each of the following: (i)2sin2theta=sqrt(3...

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  3. If A=30^@ verify that cos3A=4cos^3A-3cosA

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  4. If x=30^@ , verify that : (i) tan2x=(2tanx)/(1-tan^2x) (ii) sinx=sqr...

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  5. Verify that: sin60o=(2tan30o)/(1+tan^2 30o)=(sqrt(3))/2 (ii) cos60...

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  6. Verify that: (i) cos60^@=cos^2 30^@-sin^2 30^@=1/2

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  7. If theta is an acute angle and sintheta=costheta , find the valu...

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  8. Given that sin(A+B)=sinAcosB+cosAsinB , find the value of sin75^@ .

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  9. In a rectangle A B C D ,\ \ A B=20 c m , /B A C=60^@ . Calculate s...

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  10. Evaluate the following: (i) sin45osin30o+cos45ocos30o (ii) sin60oc...

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  11. Evaluate the following: (i) cos60ocos45o-sin60osin45o (ii) sin^2 3...

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  12. Evaluate the following: cos^2 30o+cos^2 45o+cos^2 60o+cos^2 90o (...

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  13. Evaluate the following: (i) 2sin^2 30o-3cos^2 45o+tan^2 60o (ii) s...

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  14. Evaluate the following: 4(sin^4 60o+cos^4 30o)-3(tan^2 60o-tan^2 4...

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  15. Evaluate the following: cos e c^3 30ocos60otan^3 45osin^2 90osec^2 ...

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  16. Evaluate the following: (cos0o+sin45o+sin30o)(sin90o-cos45o+cos60o)...

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  17. Evaluate the following: (i) 4/(cot^2 30o)+1/(sin^2 60o)-cos^2 45o ...

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  18. Evaluate the following: (tan^2 60o+4cos^2 45o+3sec^2 30o+5cos^2 90o)...

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  19. Evaluate the following: (tan45^@)/(cos e c\ 30^@)+(sec60^@)/(cot45^@...

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  20. Find the value of x in each of the following: (i) 2sin3x=sqrt(3) (...

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