Question

If sec theta -tan theta =4,then find cos theta

Answer 1

Answer:

Step-by-step explanation:

sec theta - tan theta =4  , let this be equation 1

we know that

sec^ theta - tan^theta = 1

(sec theta - tan theta) ( sec theta + tan theta) = 1

4 ( sec theta + tan theta) =1

sec theta + tan theta = 1/4 , let this be equation 2

on eliminating equation 1 and 2

sec theta - tan theta =4

sec theta + tan theta = 1/4

we get :

 sec theta + sec theta = 4+1/4

2sec theta = 17/4

sec theta = 17/8

cos theta = 1/sec theta

cos theta = 8/17