from the unit circle ...Hi there just wondering if someone could answer a question I have.
I've been given the function:
f(x)= cos x + sin x with a domain of [0,π] π <--- is pi (3.14)
and it wants me to determine the coordinates of the point where the tangent is horizontal.
I know first off I must take the derivative of this and I get
f ' (x)= cos x - sin x (i've just rearanged so the negative isn't infront)
0=cos x - sin x (set to zero)
sin x = cos x move sin over to make it equal
(sin x = cos x) / cos x divide both sides by cos
tan x = 1 this gives us the idenity (sinx/cosx =tanx) and 1
**this is where I get stuck I don't understand where I go from here to determine the coordinates if someone could show me it be much appreciated. Thank you