

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class
Last updated at May 29, 2023 by Teachoo
Ex 2.1, 12 Find the value of cosโ1 (1/2) + 2 sinโ1 (1/2) Solving cosโ1 (๐/๐) Let y = cosโ1 (1/2) cos y = (1/2) cos y = cos (๐ /๐) โด y = ๐ /๐ Since Range of cosโ1 is [0 , ๐] Hence, the principal value is ๐ /๐ (Since cos ๐/3 = 1/2) Solving sinโ1 (๐/๐) Let y = sinโ1 (1/2) sin y = 1/2 sin y = sin (๐ /๐) โด y = ๐ /๐ Since Range of sinโ1 is [(โ๐)/2 " , " ๐/2] Hence, the Principal Value is ๐ /๐ (Since sin ๐/6 = 1/2) Now we have cosโ1 1/2 = ๐/3 & sinโ1 1/2 = ๐/6 Solving cosโ1 ๐/๐ + 2 sinโ1 ๐/๐ = ๐/3 + 2 ร ๐/6 = ๐/3 + ๐/3 = (๐ + ๐)/3 = ๐๐ /๐