Question

Sinx+Cosx=0
Solve 0 12 years ago

Answer 1

since 0<x<360 we working in all quadarants
all possible answers must be provided

sinx + cosx = 0
sinx+ ( 1 - sin^2x) = 0
sinx = -√1-sin^2x
sin^2x = 1-sin^2x
2sin^2x = 1
sin^2x = 1/2
sinx = √1/2
sinx = .707 sinx = -.707
x = sin-1(.707) x = sine-1(-.707)
x= .785 + 2nπ x = -.785 +2nπ
x= π -.785 +2nπ x= π +.785 + 2nπ

I solved in radians .. sorry im not used to working with degrees

Answer 2

@Jennings, I think you're making it more difficult than it is :P
\[\begin{align*}\sin x+\cos x&=0\\
\sin x&=-\cos x\\
\tan x&=-1
\end{align*}\]