The value of tan9∘−tan27∘−tan63∘+tan81∘ isAnswer: 4SolutionRewrite using complementary angles: tan81∘=cot9∘ and tan63∘=cot27∘. The expression becomes tan9∘+cot9∘−tan27∘−cot27∘=sin18∘2−sin54∘2. Using sin18∘=45−1 and sin54∘=45+1, we get 5−18−5+18=4.JEE Main · 2023 · 06 Apr 2023 · Shift 2 · Integer answer