NIMCET 2011 — Mathematics PYQ
NIMCET | Mathematics | 2011The value of 1+tan215∘1−tan215∘ is:
Choose the correct answer:
- A.
1
- B.
3
- C.
23
23
Explanation
1. Recall the identity:
The formula for cos2θ in terms of tanθ is:
cos2θ=1+tan2θ1−tan2θ
2. Apply the identity to the given expression:
In this problem, θ=15∘.
1+tan215∘1−tan215∘=cos(2×15∘)
3. Simplify the angle:
cos(30∘)
4. Substitute the standard value:
From the trigonometric table, we know:
cos30∘=23
Conclusion:
The value of the expression is 23.
The correct option is (c).
Explanation
1. Recall the identity:
The formula for cos2θ in terms of tanθ is:
cos2θ=1+tan2θ1−tan2θ
2. Apply the identity to the given expression:
In this problem, θ=15∘.
1+tan215∘1−tan215∘=cos(2×15∘)
3. Simplify the angle:
cos(30∘)
4. Substitute the standard value:
From the trigonometric table, we know:
cos30∘=23
Conclusion:
The value of the expression is 23.
The correct option is (c).
