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Question : 26 of 160
Marks:
+1,
-0
Solution:
We have,
‌tan−1(x+‌)+tan−1(x−‌)‌=tan−1x‌x≠0‌‌ Now, ‌tan−1(‌| x++x− |
| 1−(x+‌)(x−‌) |
)‌=tan−1x‌⇒‌‌‌=x‌⇒‌‌2=1−x2+‌‌‌‌x2−‌+1=0‌⇒‌‌x4+x2−2=0‌‌‌(x2+2)(x2−1)=0‌‌‌x2=2⇒x=±1∴ Number of values of
x=2
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