cos2π6 + θ - sin2π6 + θ is equal to
12cos2θ
0
- 12cos2θ
12
In ∆ABC, cosC + cosAc + a + cosBb is equal to
1a
1b
c + ab
1
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
If f(x) = x2 - 10x + 25x2 - 7x + 10 and f is continuous at x = 5, then f(5) is equal to
5
10
25
If h(x) = xxx, then at x = 1, h'xhx is equal to
h(x)
1hx
1 + loghx
- loghx
ddxsin-13x - 4x3 is equal to
34 - x2
31 - x2
14 - x2
- 14 - x2
If f(x) = x2x + a, then f''(a) is equal to
4a
18a
14a
8a