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cos2thetacos2phi+sin^2(theta-phi)-sin^2(...

`cos2thetacos2phi+sin^2(theta-phi)-sin^2(theta+phi)=`

A

`sin2(theta+phi)`

B

`cos2(theta+phi)`

C

`sin2(theta-phi)`

D

`cos2(theta-phi)`

Text Solution

Verified by Experts

The correct Answer is:
B
Given expression, `cos2thetacos2phi+sin^(2)(theta-phi)-sin^(2)(theta+phi)`
`" "=cos2theta*cos2phi+sin(theta-phi+theta+phi)*sin(theta-phi-theta-phi)`
`" "=cos2theta*cos2phi-sin2theta*sin2phi`
`" "=cos(2theta+2phi)=cos2(theta+phi)`
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NCERT EXEMPLAR-TRIGONOMETRIC FUNCTIONS -OBJECTIVE TYPE QUESTIONS
  1. The minimum of 3cosx +4sin x+8 is

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  2. tan 3A-tan 2A-tan A= is equal to

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  3. The value of sin(45^(@)+theta)-cos(45^(@)-theta) is

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  4. The value of cot((pi)/(4)+theta)cot((pi)/(4)-theta) is

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  5. cos2thetacos2phi+sin^2(theta-phi)-sin^2(theta+phi)=

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  6. The value of cos12^@+cos84^@+cos156^@+cos132^@ is

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  7. If tanA=(1)/(2) and tanB=(1)/(3), then tan(2A+B) is equal to

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  8. The value of sin""(pi)/(10)sin""(13pi)/(10) is

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  9. The value of sin50^(@)-sin70^(@)+sin10^(@) is

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  10. If sintheta+costheta=1, then the value of sin2theta is

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  11. If alpha+beta=pi/4 then (1+tan alpha)(1+tan beta)=

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  12. If sintheta=(-4)/(5) and theta lies in third quadrant, then the value...

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  13. The number of solutions of equation tanx+secx=2cosx lying in the inter...

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  14. The value of sin(pi/18)+sin(pi/9)+sin((2pi)/9)+sin((5pi)/18) is

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  15. If A lies in the second quadrant and 3tanA + 4=0, then find the value ...

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  16. The value of cos^(2)48^(@)-sin^(2)12^(@) is

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  17. If tanalpha =(1)/(7) and tanbeta =(1)/(3) , then, cos2alpha is equal ...

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  18. If tantheta=(a)/(b), then bcos2theta+asin2theta is equal to

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  19. If for real values of x, costheta=x+(1)/(x), then

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  20. The value of (sin50^(@))/(sin130^(@)) is ….. .

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