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The minimum value of atan^2x+bcot^2x equ...

The minimum value of `atan^2x+bcot^2x` equals the maximum value of `asin^2theta+bcos^2theta` where `a > b > 0.` The `a/b` is 2 (b) 4 (c) 6 (d) 8

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To solve the problem, we need to find the relationship between \( a \) and \( b \) given the conditions of the minimum and maximum values of the trigonometric functions involved. ### Step-by-Step Solution: 1. **Understanding the Minimum Value of \( a \tan^2 x + b \cot^2 x \)**: - The expression \( a \tan^2 x + b \cot^2 x \) can be rewritten using the identity \( \cot^2 x = \frac{1}{\tan^2 x} \). - Let \( t = \tan^2 x \). Then, the expression becomes \( a t + \frac{b}{t} \). 2. **Finding the Minimum Value**: - To find the minimum value of \( a t + \frac{b}{t} \), we can use the AM-GM inequality: \[ a t + \frac{b}{t} \geq 2 \sqrt{a \cdot \frac{b}{t}} = 2\sqrt{ab} \] - The equality holds when \( at = \frac{b}{t} \) or \( t^2 = \frac{b}{a} \), leading to \( t = \sqrt{\frac{b}{a}} \). 3. **Setting the Minimum Value**: - Thus, the minimum value of \( a \tan^2 x + b \cot^2 x \) is \( 2\sqrt{ab} \). 4. **Understanding the Maximum Value of \( a \sin^2 \theta + b \cos^2 \theta \)**: - The expression \( a \sin^2 \theta + b \cos^2 \theta \) can be rewritten using the identity \( \cos^2 \theta = 1 - \sin^2 \theta \): \[ a \sin^2 \theta + b (1 - \sin^2 \theta) = (a - b) \sin^2 \theta + b \] 5. **Finding the Maximum Value**: - The maximum value occurs when \( \sin^2 \theta \) is maximized. If \( a > b \), the maximum value occurs at \( \sin^2 \theta = 1 \): \[ \text{Maximum value} = a - b + b = a \] 6. **Equating the Minimum and Maximum Values**: - From the problem, we have: \[ 2\sqrt{ab} = a \] 7. **Squaring Both Sides**: - Squaring both sides gives: \[ 4ab = a^2 \] 8. **Rearranging the Equation**: - Rearranging gives: \[ a^2 - 4ab = 0 \] - Factoring out \( a \): \[ a(a - 4b) = 0 \] - Since \( a > 0 \), we have: \[ a - 4b = 0 \implies a = 4b \] 9. **Finding \( \frac{a}{b} \)**: - Therefore: \[ \frac{a}{b} = 4 \] ### Final Answer: The value of \( \frac{a}{b} \) is \( 4 \).

To solve the problem, we need to find the relationship between \( a \) and \( b \) given the conditions of the minimum and maximum values of the trigonometric functions involved. ### Step-by-Step Solution: 1. **Understanding the Minimum Value of \( a \tan^2 x + b \cot^2 x \)**: - The expression \( a \tan^2 x + b \cot^2 x \) can be rewritten using the identity \( \cot^2 x = \frac{1}{\tan^2 x} \). - Let \( t = \tan^2 x \). Then, the expression becomes \( a t + \frac{b}{t} \). ...
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CENGAGE ENGLISH-TRIGONOMETRIC FUNCTIONS -Exercises
  1. The greatest value of sin^4theta+cos^4theta is

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  2. If f(x)=sin^6x+cos^6x , then range of f(x) is [1/4,1] (b) [1/4,3/4] ...

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  3. The minimum value of atan^2x+bcot^2x equals the maximum value of asin^...

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  4. Range of f(theta)=cos^2theta(cos^2theta+1)+2sin^2theta is [3/4,1] (b)...

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  5. If 0<theta<pi, then minimum value of 3sintheta+cos e c^3theta is 4 (b)...

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  6. If thetaigt0" for "1lethetalenandtheta1+theta2+theta3+...+thetan=pithe...

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  7. The set of values of lambda in R such that sin^2theta+costheta=lambda...

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  8. Let A=sin^8theta+cos^14theta, " then "A("max") is

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  9. Minimum value of y=256sin^2x+324cos e c^2xAAx in R is 432 (b) 504 ...

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  10. If a and b are positive quantities, (a gt b) find minimum positive val...

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  11. If y=(sinx+cosecx)^2+(cosx+secx)^2 then the minimum value of y,AAx in ...

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  12. The variable x satisfying the equation |sinxcosx|+sqrt(2+tan^2+cot^2x)...

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  13. If the equation cot^4x-2cos e c^2x+a^2=0 has at least one solution, th...

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  14. If cos^2x-(c-1)cosx+2cgeq6 for every x in R , then the true set of va...

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  15. If the inequality sin^2x+acosx+a^2>1+cosx holds for any x in R , then...

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  16. If (3pi)/4 lt alpha lt pi, then sqrt(2cotalpha+1/(sin^2alpha)) is equ...

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  17. The value of sectheta/sqrt(1+tan^2theta)+(cosectheta)/(sqrt(1+cot^2th...

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  18. The minimum value of the function f(x)=sinx/(sqrt(1-cos^2x))+cosx/sqrt...

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

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  20. In which of the following intervals the inequality, sinx < cos x < tan...

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