Skip to content
Question 32 of 36

Q.Prove that tan⁡−1(211)+tan⁡−1(724)=tan⁡−1(12)\tan^{-1}\left(\dfrac{2}{11}\right)+\tan^{-1}\left(\dfrac{7}{24}\right)=\tan^{-1}\left(\dfrac{1}{2}\right)

Tamil Nadu DgeTamil Nadu HSC First Year (DGE) Commerce Board 2024Subjective· 3mImportance★★★★★
89% · 32/36 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Applying the addition formula to tan⁡−1211+tan⁡−1724\tan^{-1}\tfrac2{11}+\tan^{-1}\tfrac7{24} gives tan⁡−112\tan^{-1}\tfrac12.

Formula. For AB<1AB<1, tan⁡−1A+tan⁡−1B=tan⁡−1 ⁣A+B1−AB.\tan^{-1}A+\tan^{-1}B=\tan^{-1}\!\dfrac{A+B}{1-AB}. Here A=211,B=724, AB=14264=7132<1.A=\tfrac2{11},B=\tfrac7{24},\ AB=\tfrac{14}{264}=\tfrac{7}{132}<1.

Numerator:  211+724=48+77264=125264.\ \dfrac2{11}+\dfrac7{24}=\dfrac{48+77}{264}=\dfrac{125}{264}.

Denominator:  1−7132=125132.\ 1-\dfrac7{132}=\dfrac{125}{132}.

…

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.