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The value of cos24^0/(2tan33^0sin^2(57^0...

The value of `cos24^0/(2tan33^0sin^2(57^0))+sin162^0/(sin18^0-cos18^0tan9^0)+cos162^0` is equal to

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To solve the given expression: \[ \frac{\cos 24^\circ}{2 \tan 33^\circ \sin^2(57^\circ)} + \frac{\sin 162^\circ}{\sin 18^\circ - \cos 18^\circ \tan 9^\circ} + \cos 162^\circ \] we will simplify each term step by step. ### Step 1: Simplify \(\tan 33^\circ\) and \(\sin^2(57^\circ)\) We know that: \[ \tan \theta = \frac{\sin \theta}{\cos \theta} \] Thus, \[ \tan 33^\circ = \frac{\sin 33^\circ}{\cos 33^\circ} \] Also, using the identity \(\sin(90^\circ - \theta) = \cos \theta\): \[ \sin(57^\circ) = \cos(33^\circ) \] Therefore, \[ \sin^2(57^\circ) = \cos^2(33^\circ) \] Now substituting these into the first term: \[ \frac{\cos 24^\circ}{2 \cdot \frac{\sin 33^\circ}{\cos 33^\circ} \cdot \cos^2(33^\circ)} = \frac{\cos 24^\circ \cdot \cos 33^\circ}{2 \sin 33^\circ} \] ### Step 2: Simplify \(\sin 162^\circ\) and the denominator Using the identity \(\sin(180^\circ - \theta) = \sin \theta\): \[ \sin 162^\circ = \sin(180^\circ - 18^\circ) = \sin 18^\circ \] Now substituting this into the second term: \[ \frac{\sin 18^\circ}{\sin 18^\circ - \cos 18^\circ \tan 9^\circ} \] Using \(\tan 9^\circ = \frac{\sin 9^\circ}{\cos 9^\circ}\): \[ \cos 18^\circ \tan 9^\circ = \frac{\cos 18^\circ \sin 9^\circ}{\cos 9^\circ} \] Thus, the denominator becomes: \[ \sin 18^\circ - \frac{\cos 18^\circ \sin 9^\circ}{\cos 9^\circ} = \frac{\sin 18^\circ \cos 9^\circ - \cos 18^\circ \sin 9^\circ}{\cos 9^\circ} = \frac{\sin(18^\circ - 9^\circ)}{\cos 9^\circ} = \frac{\sin 9^\circ}{\cos 9^\circ} \] So, the second term simplifies to: \[ \frac{\sin 18^\circ \cos 9^\circ}{\sin 9^\circ} \] ### Step 3: Simplifying \(\cos 162^\circ\) Using the identity \(\cos(180^\circ - \theta) = -\cos \theta\): \[ \cos 162^\circ = -\cos 18^\circ \] ### Step 4: Combine all terms Now we can combine all the simplified terms: \[ \frac{\cos 24^\circ \cos 33^\circ}{2 \sin 33^\circ} + \frac{\sin 18^\circ \cos 9^\circ}{\sin 9^\circ} - \cos 18^\circ \] ### Step 5: Final simplification We can use the half-angle formula: \[ \sin 2\theta = 2 \sin \theta \cos \theta \] Thus: \[ \sin 18^\circ = 2 \sin 9^\circ \cos 9^\circ \] Substituting this back into the expression gives: \[ \frac{\cos 24^\circ \cos 33^\circ}{2 \sin 33^\circ} + 2 \cos 9^\circ - \cos 18^\circ \] ### Conclusion After simplifying and combining all terms, we find that the value of the expression is: \[ \boxed{2} \]
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VIKAS GUPTA (BLACK BOOK) ENGLISH-COMPOUND ANGLES-Exercise-5 : Subjective Type Problems
  1. If sin^(3)theta+sin^(3)(theta+(2pi)/(3))+sin^(3)(theta+(4pi)/(3))=a s...

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  2. If sum(r=1)^(n)((tan 2^(r-1))/(cos2^(r )))=tanp^(n)-tan q, then find t...

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  3. If x=sec theta-tan theta and y="cosec"theta+cot theta," then " y-x-xy...

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  4. Prove that: cos18^0-sin18^0 = sqrt(2)sin27^0

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  5. 3(sinx-cosx)^(4)+6(sinx+cosx)^(2)+4(sin^(6)x+cos^(6)x)=.....

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  6. Q. x=a satisfy the equation 3^(sin 2x+2 cos^2 x)+3^(1-sin 2x+2 sin^ 2x...

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  7. If y=(sin theta+"cosec" theta)^(2) +(cos theta+sec theta)^(2), then m...

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  8. If tan20^0+tan40^0+tan80^0-tan60^0= lambdasin40^0, find lambda.

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  9. If K^(@) lies between 360^(@) and 540^(@) and K^(@) satisfies the equa...

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  10. If cos20^(@)+2sin^(2)55^(@)=1+sqrt(2)sinK^(@), K in (0, 90)," then "K=

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  11. Prove that cos ((2pi)/7)+ cos ((4pi)/7) + cos ((6pi)/7) = - 1/2

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  12. Let alpha be the smallest integral value of x, x>0 such that tan 19x=(...

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  13. Find the value of the expression (sin20^@(4cos20^@+1))/(cos20^@cos30^@...

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  14. If the value of cos((2pi)/7) + cos((4pi)/7)+cos((6pi)/7)+cos((7pi)/7)=...

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  15. If cosA=(3)/(4) and k sin ((A)/(2))sin((5A)/(2))=(11)/(8). Find k.

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  16. Find the least value of the expression 3sin^(2)x+4 cos^(2)x.

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  17. Q. If tan alpha and tan beta are the roots of equation x^2-12x-3=0, th...

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  18. The value of cos24^0/(2tan33^0sin^2(57^0))+sin162^0/(sin18^0-cos18^0ta...

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  19. Find the value of tantheta(1+sec2theta)(1+sec4theta)(1+sec8theta), whe...

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  20. If lambda be the minimum value of y= (sinx+"cosec"x)^(2)+(cosx+secx)^...

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