Question
Question: If \(\tan ^ { - 1 } x + \tan ^ { - 1 } y = \frac { \pi } { 4 }\) then....
If tan−1x+tan−1y=4π then.
A
x+y+xy=1
B
x+y−xy=1
C
x+y+xy+1=0
D
x+y−xy+1=0
Answer
x+y−xy=1
Explanation
Solution
tan−1(1−xyx+y)=tan−11
x+y+xy=1.
If tan−1x+tan−1y=4π then.
x+y+xy=1
x+y−xy=1
x+y+xy+1=0
x+y−xy+1=0
x+y−xy=1
tan−1(1−xyx+y)=tan−11
x+y+xy=1.