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Evaluate the ((3 cos 43^(@))/(sin 47^...

Evaluate the
`((3 cos 43^(@))/(sin 47^(@)))^(2) - (cos 37^(@) "cosec" 53^(@))/(tan 5^(@) tan 25^(@) tan 45^(@) tan 65^(@) tan 85^(@))`

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To evaluate the expression \[ \left(\frac{3 \cos 43^\circ}{\sin 47^\circ}\right)^2 - \frac{\cos 37^\circ \csc 53^\circ}{\tan 5^\circ \tan 25^\circ \tan 45^\circ \tan 65^\circ \tan 85^\circ} \] we will simplify it step by step. ### Step 1: Simplify the first term Using the identity \(\cos(90^\circ - \theta) = \sin(\theta)\), we can rewrite \(\cos 43^\circ\) as: \[ \cos 43^\circ = \sin(90^\circ - 43^\circ) = \sin 47^\circ \] Thus, the first term becomes: \[ \frac{3 \cos 43^\circ}{\sin 47^\circ} = \frac{3 \sin 47^\circ}{\sin 47^\circ} = 3 \] Now squaring this gives: \[ (3)^2 = 9 \] ### Step 2: Simplify the second term For the second term, we rewrite \(\cos 37^\circ\) using the identity \(\cos(90^\circ - \theta) = \sin(\theta)\): \[ \cos 37^\circ = \sin(90^\circ - 53^\circ) = \sin 53^\circ \] Thus, the second term becomes: \[ \frac{\cos 37^\circ \csc 53^\circ}{\tan 5^\circ \tan 25^\circ \tan 45^\circ \tan 65^\circ \tan 85^\circ} = \frac{\sin 53^\circ \cdot \csc 53^\circ}{\tan 5^\circ \tan 25^\circ \tan 45^\circ \tan 65^\circ \tan 85^\circ} \] Since \(\csc 53^\circ = \frac{1}{\sin 53^\circ}\), we have: \[ \sin 53^\circ \cdot \csc 53^\circ = 1 \] Now we need to evaluate the denominator: \[ \tan 5^\circ \tan 25^\circ \tan 45^\circ \tan 65^\circ \tan 85^\circ \] Using the identity \(\tan(90^\circ - \theta) = \cot(\theta)\), we can rewrite: \[ \tan 85^\circ = \cot 5^\circ, \quad \tan 65^\circ = \cot 25^\circ \] Thus, we can pair them: \[ \tan 5^\circ \tan 85^\circ = 1, \quad \tan 25^\circ \tan 65^\circ = 1 \] And we know: \[ \tan 45^\circ = 1 \] So the entire product simplifies to: \[ \tan 5^\circ \tan 25^\circ \tan 45^\circ \tan 65^\circ \tan 85^\circ = 1 \cdot 1 \cdot 1 = 1 \] ### Step 3: Combine the results Now substituting back into the expression, we have: \[ 9 - 1 = 8 \] ### Final Answer Thus, the value of the expression is: \[ \boxed{8} \]
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VK GLOBAL PUBLICATION-INTRODUCTION TO TRIGONOMETRY-PROFICIENCY EXERCISE (SHORT ANSWER QUESTIONS-II)
  1. Prove that : (i) (sin 70^@)/(cos 20^@)+(cosec 20^@)/(sec 70^@)-2cos ...

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  2. Evaluate : cos e c(65^0+theta)-sec(25^0-theta)-tan(55^0-theta)+cot(...

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  3. Evaluate the ((3 cos 43^(@))/(sin 47^(@)))^(2) - (cos 37^(@) "cosec...

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  4. If sec 2A=cosec (A-42^@), where 2A is an acute angle, find the value o...

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  5. If sin (A - B) = 0 , cos (A + B) = 0, 0^(@) lt A + B le 90^(@), find...

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  6. If tan (A + B) = sqrt(3) and tan (A - B) = 0, 0^(@) lt A + B le 90^(@...

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  7. Prove : ( 1+ tan^2 theta )(1 + sin theta )(1 - sin theta) = 1.

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  8. If sin theta+cos theta=sqrt3, then prove that tan theta+cot theta=1

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  9. .If alpha+beta=90^(@), show that sqrt(cos alpha*csc beta-cos alpha*sin...

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  10. If tan theta =a/b, prove that (a sin theta- b cos theta)/(a sin theta+...

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  11. If sectheta=5/4 , find the value of (sintheta-2costheta)/(tantheta-...

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  12. If theta=30o , verify that: (i) tan2theta=(2tantheta)/(1-tan^2theta...

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  13. If theta=30o , verify that: (i) cos2theta=(1-tan^2theta)/(1+tan^2th...

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

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

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  16. If cottheta=(15)/8,t h e ne v a l u a t e((2+2sintheta)(1-sintheta)/((...

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  17. If sectheta=x+1/(4x),p rov et h a t :sectheta+tantheta=2xor ,1/(2x)

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  18. If sqrt(3) tan theta=3 sin theta and theta!=0 then find the value of s...

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  19. If cos e c\ theta=(13)/(12) , find the value of (2sintheta-3\ cos\ ...

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  20. If sintheta=(a^2-b^2)/(a^2+b^2) then find 1+tantheta*costheta.

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