Question

Help please: Show that 3x + 2cosx + 5 = 0 has exactly one real root?

Answer 1

cos x = (-5 -3x) / 2

and cos x lies b/w -1 and 1
so can you find the range of all possible values of x ?

Answer 2

@ harsimran_hs4:
Is there a way in which you can explain how to solve the problem using the Rolle's Thrm, Intermediate Value Thrm or the Mean Value Thrm? That's how the problem is asking me to solve it that's why. Please and thank you :)

Answer 3

@dan815: Hi? lol..