Question

4. The equation sinx + cosx=0 has at least one root in the interval


(a) (-pie/2,0)        (b)(0, pie)
      (c) (-pie/2, pie/2)         (d)
none of these

Answer 1

sin x + cos x = 0
⇒sin x= -cos x
⇒tan x = -1
⇒ x = -π/4 and 3π/4

So answer is a,b,c