What is 1sin10° - 3cos10° = ?
0
1
2
4
If k = sinπ18sin5π18sin7π18, then what is the value of k ?
12
14
18
116
The expression sinα + sinβcosα + cosβ = ?
tanα + β2
cotα + β2
sinα + β2
What is the value of tan18° ?
5 - 110 + 25
5 - 110 + 5
10 + 255 - 1
10 + 55 - 1
If tanα + β = 2 and tanα + β = 1, then tan2α = ?
- 3
- 2
- 13
Consider the following for triangle ABC :
I. sinB + C2 = cosA2II. tanB + C2 = cotA2III. sinB + C = sinAIV. tanB +C = - tanA
Which of the above are correct ?
1 and 3
1 and 2
1 and 4
2 and 3
If sinθ = 3sin(θ + 2α), then the value of tan (θ + α)+ 2tanα is equal to
- 1
If secθ - cscθ = 43, then what is sinθ - cosθ = ?
- 2 only
12 only
Both - 2 and 12
Neither 12 nor - 2
C.
∵ secθ - cscθ = 43⇒ 1cosθ - 1sinθ = 43⇒ sinθ - cosθcosθ ×sinθ = 43⇒ sinθ - cosθ = 43cosθ . sinθNow, secθ - cscθ2 = 169⇒ sec2θ + csc2θ = 2secθcscθ = 169⇒ 1cos2θ + 1sin2θ - 2sinθcosθ = 169⇒ sin2θ + cos2θ - 2sinθcosθcos2θsin2θ = 169⇒ 1 - 2sinθcosθcos2θsin2θ = 169⇒ 16cos2θsin2θ + 18cosθsinθ - 9 = 0⇒ 16cos2θsin2θ + 24cosθsinθ - 6cosθsinθ - 9 = 0⇒8cosθsinθ2cosθsinθ + 3 - 32cosθsinθ + 3 = 0⇒ 2cosθsinθ + 38cosθsinθ - 3 = 0⇒ cosθsinθ = - 32 or cosθsinθ = 38∴ sinθ - cosθ = 43 × 38 = 12
The value of tan(9)° - tan(27)° - tan(63)° + tan(81)° is equal to :
The value of 3csc20° - sec20° = ?
- 4