3.) Show that the equation 3x + 2 cosx -|- 5 = 0 has exactly one real root. (x)= 3x+ 2405x+5 is continuous on (-20,20) and f /0) = 0+ 2+5 =7 70 .: By the int. Value theorem, $/-1)= -317 -2+5 : - 311 +340 Since fox) is continuous, s(x ) has at least one root on (- Th, 0)