Question

If x = sin αy = sin βz = sin (α + β) then cos (α + β) =

Solution

Correct option is

z2 – x2 – y2 = sin2 (α + β) – sin2 α – sin2 β

    = sin (α + β + α) sin (α + β - α) – sin2 β

    = sin β [sin (2α + β) – sin β]

    

       

SIMILAR QUESTIONS

Q1

If sin x + sin2 x = 1, then the value of cos12 x + 3 cos10 x + 3 cos8 x + cos6 x – 1 is equal to

Q2

The value of

      

Q3

If θ lies in the first quadrant and cos θ = 8/17, then the value of cos (300 +θ) + cos (450 – θ) + cos (1200 – θ) is

Q4

If A lies in the second quadrant and 3 tan A + 4 = 0, the value of 2 cot A – 5 cos A + sin A is equal to

Q5

The value of the determinant

                          

Is zero if

Q6

  is equal to

Q7

An angle α is divided into two parts so that the ratio of the tangents of these parts is λ. If the difference between these parts is x then sinx/sinα is equal to

Q8

 

 or equal to

Q9

Given θ Ïµ (0,π/4) and t1 = (tan θ)tanθ t2 = (tan θ)cotθt3 = (cot θ)tanθand t4 = (cot θ)cotθ then

Q10

The radius of the circle