How do i find the value of cos(theta) if theta was given as 75(+/-)5? Ans:____(+/-)_____. How do i even start with this? How do i find the uncertainty of cos (theta)? Do i use the uncertainty of theta or the fractional uncertainty? Or do i just find cos 80, cos 75 and cos 70 and then find the uncertainty by deducing it from the found values/.? Any help will truly be appreciated. Thanks.