Introducing your new favourite teacher - Teachoo Black, at only โน83 per month

Formulae based

Inverse Trigonometry Formulas

Example 3 (i) Important Deleted for CBSE Board 2023 Exams

Ex 2.2,1 Deleted for CBSE Board 2023 Exams

Ex 2.2, 2 Important Deleted for CBSE Board 2023 Exams

Example 8 Deleted for CBSE Board 2023 Exams

Ex 2.2, 12 Important Deleted for CBSE Board 2023 Exams

Ex 2.2, 14 Important Deleted for CBSE Board 2023 Exams

Example 4 Deleted for CBSE Board 2023 Exams

Ex 2.2, 3 Deleted for CBSE Board 2023 Exams

Misc. 8 Important Deleted for CBSE Board 2023 Exams

Ex 2.2, 4 Important Deleted for CBSE Board 2023 Exams You are here

Ex 2.2, 15 Important Deleted for CBSE Board 2023 Exams

Example 13 Important Deleted for CBSE Board 2023 Exams

Misc. 14 Deleted for CBSE Board 2023 Exams

Misc 17 (MCQ) Deleted for CBSE Board 2023 Exams

Misc. 13 Important Deleted for CBSE Board 2023 Exams

Example 10 Important Deleted for CBSE Board 2023 Exams

Misc. 3 Deleted for CBSE Board 2023 Exams

Misc. 4 Important Deleted for CBSE Board 2023 Exams

Misc 12 Important Deleted for CBSE Board 2023 Exams

Misc 16 (MCQ) Important Deleted for CBSE Board 2023 Exams

Last updated at May 12, 2021 by Teachoo

Ex 2.2, 4 Prove 2tanโ1 1/2 + tanโ1 1/7 = tanโ1 31/17 Value of 2tanโ1 ๐/๐ We know that 2tanโ1x = tanโ1 ((๐๐ฑ )/( ๐ โ ๐ฑ^๐ )) Replacing x with 1/2 2tanโ1 1/2 = tanโ1 (2 ร 1/2)/(1 โ (1/2)2) = tanโ1 (1/(1 โ 1/4)) = tanโ1 (1/((4 โ 1)/4)) = tanโ1 (1/(3/4)) = tanโ1 (๐/๐) Solving L.H.S. 2tanโ1 1/2 + tanโ1 1/7 Putting value of 2tanโ1 1/2 = tanโ1 4/3 + tanโ1 1/7 = tanโ1 (1/(1 โ 1/4)) = tanโ1 (1/((4 โ 1)/4)) = tanโ1 (1/(3/4)) = tanโ1 (๐/๐) Solving L.H.S. 2tanโ1 1/2 + tanโ1 1/7 Putting value of 2tanโ1 1/2 = tanโ1 4/3 + tanโ1 1/7 Using tanโ1x + tanโ1y = tanโ1 ((๐ + ๐ )/( ๐โ ๐๐)) Replacing x by 4/3 and y by 1/(7 )= tanโ1 ((๐/๐ + ๐/๐ )/( ๐โ ๐/๐ ร ๐/๐)) = tanโ1 (((4 ร 7 +3 ร 1 )/( 7 ร 3) )/( (7 ร 3 โ 4)/(7 ร 3))) = tanโ1 (((28 + 3 )/( 21) )/( ( 21 โ 4)/21)) = tanโ1 ((31/( 21) )/(17/21)) = tanโ1 (31/21ร21/17) = tanโ1 (๐๐/๐๐) = R.H.S. Hence, L.H.S. = R.H.S. Hence Proved