tanθ + cotθ = 2 = 2, then sinθ is equal to
12
13
1
If θ = π6, then the 10th term of 1 + cosθ + isinθ + cosθ + isinθ2 + cosθ + isinθ3 + ...is equal to
i
- 1
- i
sin5θsinθ is equal to
16cos4θ - 12cos2θ + 1
16cos4θ+ 12cos2θ + 1
16cos4θ - 12cos2θ - 1
16cos4θ + 12cos2θ - 1
cos2π6 + θ - sin2π6 + θ is equal to
12cos2θ
0
- 12cos2θ
In ∆ABC, cosC + cosAc + a + cosBb is equal to
1a
1b
c + ab
In ∆ABC, ab2 - c2 + cb2 - a2 = 0, then B is equal to
π2
π4
2π3
π3
D.
We have,ab2 - c2 + cb2 - a2 = 0⇒ 2RsinA4R2sin2B - sin2C + 2RsinC4R2sin2B - sin2A = 0⇒12RsinAsinB + CsinB - C + 12RsinCsinB + CsinB - A = 0⇒ 12RsinAsinAsinB - C + 12RsinCsinCsinB - A = 0⇒ 12R1sinB - C + 12R1sinB - A = 0⇒ sinB - C + sinB - A = 0⇒ 2sin2B - A - C2cos- C + A2 = 0 ⇒ sin2B - A - C2 = 0⇒ 2B = A + C⇒ 2B = 180° - B⇒ 3B = 180°⇒ B = π3
In ∆ABC,a2sin(2C) + c2sin(2A) is equal to
∆
2∆
3∆
4∆
The shadow of a tower standing on a level ground is found to be 60m longer when the sun'saltitude is 30° than when it is 45°.The height of the tower is
30m
90m
603m
303 + 1m
If cosecθ = p + qp - q,then cotπ4 + θ4 is equal to
pq
qp
From a point on the level ground, the angle of elevation of top of a pole is 30° on moving 20metres nearer,the angle of elevation is 45°. Then,the height of the pole in metres, is
103 - 1
15
20