70∘53;2∘47,60∘;300∘ Explanation 3cos 2x cos x 2 = 0 Replace cos 2x by (2cos2x− 1) > 3(2cos2x− 1) cosx 2 = 0 How to solve a equation like 2cosx cos(x30) = 0 using scientific calculator First let's start by finding a solution to the given problem by using the Texas Instruments 92 Plus scientific calculator , or