Thea value of cos pi/14*cos 3pi/14 * cos 5pi/14 is ? Share with your friends Share 1 Poonam Mittal answered this Here is the link similar to your query.https://www.meritnation.com/ask-answer/question/what-is-the-value-of2cos-pi-13cos-9pi-13-cos-3pi-13-c/trigonometric-functions/2331501 -6 View Full Answer Ganapathy Subramanian Tkg answered this = sin pi/14 cos (pi/2 - 3/pi/14) cos (pi/2 - 5 pi/14)= sin pi/14 cos 4pi/14 cos 2pi/14= sin pi/14 cos 2pi/14 cos 4pi/14= (cos pi/14 sin pi/14 cos 2pi/14 cos 4pi/14)/ cos pi/14= 1/2( sin 2pi/14 cos 2pi/14 cos 4pi/14)/ cos pi/14= 1/4 ( sin 4pi/4 cos 4pi/14)/ cos pi/ 14= 1/8( sin 8pi/14)/ cos pi/14= 1/8 (sin (pi-8pi/14)) / cos pi/14= 1/8 sin 6pi/14/ (cos pi/14)= 1/8 cos pi/14 / cos pi/14= 1/8 -3
