InterviewSolution
Saved Bookmarks
| 1. |
Solve `7 cos^(2)x+sin x cos x-3=0`. |
|
Answer» Correct Answer - `x=n pi +(3pi)/4 and x=k pi +"tan"^(-1) 4/3 (k, n in Z)` `7 cos^(2) x+sin x cos x-3=0` Dividing by `cos^(2)x`, we get `7+tan x-3 sec^(2) x=0` or `7+tan x-3 (1+tan^(2) x)=0` or `3 tan^(2) x-tan x-4 =0` or `(tan x+1) (3 tan x-4)=0` or `tan x=-1` and `tan x=4/3` `rArr x=npi +(3pi)/4, n in Z` and `x=kpi+tan^(-1) (4/3), k in Z` |
|