If 6cos
2
θ+cosθ=2, 0
∘
<θ<90
∘
, then the value of (cscθ+cotθ+tanθ) is:
- A3
3
- B3
2
- C3
6
- D3
4
Solution & Step-by-step Explanation
Given equation:
6cos
2
θ+cosθ−2=0
Let cosθ=x. The equation becomes a quadratic equation:
6x
2
+x−2=0
6x
2
+4x−3x−2=0
2x(3x+2)−1(3x+2)=0
(2x−1)(3x+2)=0
So, x=
2
1
or x=−
3
2
.
Since 0
∘
<θ<90
∘
, cosθ must be positive.
cosθ=
2
1
⟹θ=60
∘
Now, substituting θ=60
∘
into the required expression:
csc60
∘
+cot60
∘
+tan60
∘
=
3
2
+
3
1
+
3
=
3
2+1+3
=
3
6
6cos
2
θ+cosθ−2=0
Let cosθ=x. The equation becomes a quadratic equation:
6x
2
+x−2=0
6x
2
+4x−3x−2=0
2x(3x+2)−1(3x+2)=0
(2x−1)(3x+2)=0
So, x=
2
1
or x=−
3
2
.
Since 0
∘
<θ<90
∘
, cosθ must be positive.
cosθ=
2
1
⟹θ=60
∘
Now, substituting θ=60
∘
into the required expression:
csc60
∘
+cot60
∘
+tan60
∘
=
3
2
+
3
1
+
3
=
3
2+1+3
=
3
6