NIMCET 2014 — Mathematics PYQ
NIMCET | Mathematics | 2014If tanA−tanB=x and cotB−cotA=y, then cot(A−B) is equal to:
Choose the correct answer:
- A.
x1+y1
(Correct Answer) - B.
x1−y1
- C.
−x1+y1
- D.
−x1−y1
x1+y1
Explanation
Solution
Step 1: Simplify the second given equation.
We are given:
Using the identity cotθ=tanθ1:
Taking the LCM on the left side:
Step 2: Substitute the value of x.
From the first given equation, we know that tanA−tanB=x. Substituting this into our simplified equation:
Step 3: Find tan(A−B).
Using the compound angle formula for tangent:
Substitute the values of (tanA−tanB) and (tanAtanB):
Step 4: Find cot(A−B).
Since cot(A−B)=tan(A−B)1:
Splitting the fraction:
Final Answer:
The correct option is 1: x1+y1.
Explanation
Solution
Step 1: Simplify the second given equation.
We are given:
Using the identity cotθ=tanθ1:
Taking the LCM on the left side:
Step 2: Substitute the value of x.
From the first given equation, we know that tanA−tanB=x. Substituting this into our simplified equation:
Step 3: Find tan(A−B).
Using the compound angle formula for tangent:
Substitute the values of (tanA−tanB) and (tanAtanB):
Step 4: Find cot(A−B).
Since cot(A−B)=tan(A−B)1:
Splitting the fraction:
Final Answer:
The correct option is 1: x1+y1.