If secA-tanA=4 then prove that cosA=8/17

Asked by devarajsudheerkumar2018 | 10th Jan, 2020, 09:31: PM

Expert Answer:

Given: secA-tanA=4
rightwards double arrow s e c A minus 4 equals tan A
rightwards double arrow s e c squared A plus 16 minus 8 s e c A equals tan squared A
rightwards double arrow s e c squared A minus tan squared A plus 16 equals 8 s e c A
rightwards double arrow 1 plus 16 equals 8 s e c A
rightwards double arrow 17 equals 8 s e c A
rightwards double arrow s e c A equals 17 over 8
rightwards double arrow cos A equals 8 over 17

Answered by Renu Varma | 13th Jan, 2020, 10:20: AM