## anonymous 5 years ago find the slope and the equation of the tangent line for y=x-cos2x at (0,-1)

1. watchmath

$$y'=1+2\sin(2x)$$ So at $$(0,-1)$$ the slope is 1. Then the line is $$y=x+b$$. Plugin $$x=0,y=-1$$ we conclude that $$b=-1$$. So $$y=x-1$$.

2. myininaya

y'=1-2(-sin(2x))=1+2sin(2x) y'(0)=1+2sin(0)=1+2(0)=1 so the slope at (0,-1) is 1 y=mx+b equation for tangent line y=x+b since m=1 so (x,y)=(0,-1) -1=0+b b=-1 so y=x-1

3. anonymous

you are a stud!