If ecos⁡x−e−cos⁡x=4 then the value of cos x, is

Let ecos⁡x=y . Then ,ecos⁡x−e−cos⁡x=4⇒y−1y=4⇒y2−4y−1=0⇒y=2±5⇒y=2+5 as y>0⇒ecos⁡x=2+5⇒cos⁡x=loge⁡(2+5)Clearly , logc⁡(2+5)>1 and cos⁡x≤1 So, there is no value of cos x  satisfying the given equation