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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 A=30^(@) verify that cos3A=4cos^(3)A-3cos A

If A =30^(@) ,verify that cos2A =cos^(2)A-sin^(2)A .

If A = 30^(@) and B = 60^(@) , verify that cos (A + B) = cos A cos B - sin A sin B.

If sec A=(5)/(4), verify that (3sin A-4sin^(3)A)/(4cos^(3)A-3cos A)=(3tan A-tan^(3)A)/(1-3tan^(2)A)

If A= 30^(@) and B=60^(@) verify that: sin (A+B)= sin A cos B +cosA sin B.

Prove that: cos5A=16cos^(5)A-20cos^(3)A+5cosA

If theta=30o, verify that: ( i )cos2 theta=(1-tan^(2)theta)/(1+tan^(2)theta)( ii) cos3 theta=4cos^(3)theta-3cos theta

If sec A=(17)/(8), verify that (3-4sin^(2)A)/(4cos^(2)A-3)=(3-tan^(2)A)/(1-3tan^(2)A)

If cosA+cosB+cosC=0,sinA+sinB+sinC=0andA+B+C=180^(@) then the value of cos3A+cos3B+cos3C is :

Prove that: cos A+cos3A+cos5A+cos7A=4cos A cos2A cos4A

RD SHARMA-TRIGONOMETRIC RATIOS-All Questions
  1. Solve each of the following equations when 0o<theta<90o . 2sin^2the...

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

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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 (ii) 4(sin^4 30^...

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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=60o . Calculate ...

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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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