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If 2cos""(A)/(2)=sqrt(1+sinA)+sqrt(1-sin...

If `2cos""(A)/(2)=sqrt(1+sinA)+sqrt(1-sinA), thenA/2` iles between,

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To solve the equation \( \frac{2 \cos(A/2)}{2} = \sqrt{1 + \sin A} + \sqrt{1 - \sin A} \), we will simplify and analyze the expressions step by step. ### Step 1: Simplify the Left Side The left side simplifies to: \[ \cos(A/2) \] ### Step 2: Simplify the Right Side The right side is: \[ \sqrt{1 + \sin A} + \sqrt{1 - \sin A} \] Using the identity \( \sin A = 2 \sin(A/2) \cos(A/2) \) and \( 1 = \sin^2(A/2) + \cos^2(A/2) \), we can rewrite \( 1 + \sin A \) and \( 1 - \sin A \). ### Step 3: Rewrite \( \sqrt{1 + \sin A} \) We can express \( 1 + \sin A \) as: \[ 1 + \sin A = 1 + 2 \sin(A/2) \cos(A/2) = \sin^2(A/2) + \cos^2(A/2) + 2 \sin(A/2) \cos(A/2) \] This can be rewritten as: \[ (\sin(A/2) + \cos(A/2))^2 \] Thus, \[ \sqrt{1 + \sin A} = |\sin(A/2) + \cos(A/2)| \] ### Step 4: Rewrite \( \sqrt{1 - \sin A} \) Similarly, for \( 1 - \sin A \): \[ 1 - \sin A = 1 - 2 \sin(A/2) \cos(A/2) = \sin^2(A/2) + \cos^2(A/2) - 2 \sin(A/2) \cos(A/2) \] This can be rewritten as: \[ (\sin(A/2) - \cos(A/2))^2 \] Thus, \[ \sqrt{1 - \sin A} = |\sin(A/2) - \cos(A/2)| \] ### Step 5: Combine the Right Side Now, we can express the right side as: \[ |\sin(A/2) + \cos(A/2)| + |\sin(A/2) - \cos(A/2)| \] ### Step 6: Set Up the Equation Now we have: \[ \cos(A/2) = |\sin(A/2) + \cos(A/2)| + |\sin(A/2) - \cos(A/2)| \] ### Step 7: Analyze Cases We need to analyze the cases based on the signs of \( \sin(A/2) \) and \( \cos(A/2) \). 1. **Case 1**: If \( \sin(A/2) \geq \cos(A/2) \): \[ \cos(A/2) = 2 \sin(A/2) \] This leads to \( \tan(A/2) = \frac{1}{2} \). 2. **Case 2**: If \( \sin(A/2) < \cos(A/2) \): \[ \cos(A/2) = 0 \] This leads to \( A/2 = \frac{\pi}{2} + n\pi \). ### Step 8: Find the Range of \( A/2 \) From the first case, \( \tan(A/2) = \frac{1}{2} \) implies: \[ A/2 = \tan^{-1}\left(\frac{1}{2}\right) \] This value lies between \( -\frac{\pi}{4} \) and \( \frac{\pi}{4} \). ### Conclusion Thus, the value of \( A/2 \) lies between: \[ -\frac{\pi}{4} < A/2 < \frac{\pi}{4} \]
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OBJECTIVE RD SHARMA ENGLISH-TRIGONOMETRIC RATIOS AND IDENTITIES-Exercise
  1. If sintheta-costhetalt0, then theta lies between

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  2. Within what limits must A/2 lies if 2sinA/2=-sqrt(1+sinA)-sqrt(1-sinA)...

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  3. If 2cos""(A)/(2)=sqrt(1+sinA)+sqrt(1-sinA), thenA/2 iles between,

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  4. Find the angle theta whose cosine is equal to its tangent.

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  5. Prove that cos((2pi)/(15))cos((4pi)/(15))cos((8pi)/(15))cos((14pi)/(15...

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  6. Prove:cos(pi/15)cos((2pi)/15)cos((3pi)/15)cos((4pi)/15)cos((5pi)/15)co...

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  7. The value of tan 5 theta is

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  8. If costheta=cos alphacosbeta, then tan((theta+alpha)/(2))tan((theta-al...

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  9. If abs(cos theta{sin theta+sqrt(sin^2theta+sin^2alpha)})lek, then the ...

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  10. The value of sin10^@+sin20^@+sin30^@...+sin360^@ is equal to -

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  11. Find the value of the expression 3[sin^(4)((3pi)/(2)-alpha)+sin^(4)(...

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  12. If A+B=(pi)/(4),then (tanA+1)(tanB+1) is equal to

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  13. If sinA+sinB=a and cosA+cosB=b,then cos(A+B)

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  14. If an angle theta is divided into two parts A and B such that A-B=x an...

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  15. The value of the expression is

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  16. If tan((theta)/(2))=5/2and tan((phi)/(2))=3/4, the value of cos(theta+...

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  17. If alpha,beta,gamma, in (0,pi/2) , then prove that (s i(alpha+beta+gam...

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  18. If sin x+siny=3(cosy-cosx),then the value of (sin3x)/(sin3y), is

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  19. If cosx=tany ,cosy=tanz ,cosz=tanx , then the value of sinx is 2cos18^...

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  20. If k=sin^(6)x+cos^(6)x, then k belongs to the interval

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