If cos x = sin y and cot (x - 40°) = tan (50° - y), then the value of x and y are:
x = 70°, y = 20°
x = 75°, y = 15°
x = 85°, y = 5°
x = 80°, y = 10°
C.
x = 85°, y = 5°
cosx = siny
cosx = cos(90° - y)
x = 90° - y
x + y = 90° ...(i)
cot (x - 40°) = tan (50° - y)
cot (x - 40°) = cot (90° - 50° + y)
x - 40° = 40° + y
x - y = 80° ...(ii)
Solving (i) and (ii),
x = 85° and y = 5°
If sin θ + sin2θ = 1, then the value of cos12 θ + 3 cos 10 θ + 3 cos8 θ + cos6 θ - 1 is
0
1
-1
2
If x, y are positive acute angles x + y < 90° and sin (2x - 20°) = cos (2y + 20°), then the values of sec (x + y) is
1
0