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Solve: 2sin^2x+sin^2 2x=2...

Solve: `2sin^2x+sin^2 2x=2`

A

`(pi)/(6)`

B

`(pi)/(4)`

C

`(pi)/(3)`

D

`(pi)/(2)`

Text Solution

Verified by Experts

The correct Answer is:
B, D
We have,
`2"sin"^(2) theta + "sin"^(2) 2theta = 2`
`rArr 1-"cos"2 theta + 1 - "cos"^(2) 2 theta = 2`
` rArr "cos"2theta( 1 +"cos"2 theta) = 0`
`rArr "cos" 2 theta = 0 "or cos"2 theta = -1`
`rArr 2theta = (pi)/(2) "or cos" 2 theta = pi rArr theta = (pi)/(4), (pi)/(2)`
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OBJECTIVE RD SHARMA ENGLISH-TRIGONOMETRIC EQUATIONS AND INEQUATIONS-Chapter Test
  1. Solve: 2sin^2x+sin^2 2x=2

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  2. If |k|=5 and 0^(@) le theta le 360^(@) , then the number of different...

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  3. The number of all the possible triplets (a1,a2,a3) such that a1+a2cos(...

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  4. The number of all possible 5-tuples (a(1),a(2),a(3),a(4),a(5)) such th...

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  5. General solution of the equation, cos x cdot cos 6x = -1 is =

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  6. The values of x satisfying the system of equation 2^("sin" x - "cos"...

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  7. The general solution of the equation "tan" 3x = "tan" 5x, is

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  8. The number of all possible ordered pairs (x, y), x, y in R satisfying ...

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  9. If the expression ([s in(x/2)+cos(x/2)-i t a n(x)])/([1+2is in(x/2)])...

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  10. Show that the equation , sec theta + "cosec" theta = c has two roots...

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  11. Show that the equation , sec theta + "cosec" theta = c has two roots...

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  12. If theta(1), theta(2), theta(3), theta(4) are roots of the equation "s...

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  13. If sin(pi cos theta) = cos(pi sin theta), then the value of cos(the...

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  14. If tan(pi cos theta )= cot (pi sin theta ) ,then cos^(2)(theta -pi/...

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  15. The general solution of "tan" ((pi)/(2)"sin" theta) ="cot"((pi)/(2)"co...

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  16. The most general value of theta which satisfy both the equation cos th...

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  17. The number of solutions of the x+2tanx = pi/2 in [0.2pi] is

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  18. If "sin" (pi "cot" theta) = "cos" (pi "tan" theta), "then cosec" 2 the...

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  19. The number of distinct roots of the equation A"sin"^(3) x + B"cos"^(3...

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  20. Values of x between 0 and 2 pi which satisfy the equation sin x sqr...

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  21. If Cos20^0=k and Cosx=2k^2-1, then the possible values of x between 0^...

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