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**OhCurtis** Solve for 0 <x< 360 degrees

Okay this is probably a stupid question but I'm really not doing so good with this unit so far.

Apparently to get the answer you have to take a squaring approach

sinx=-cosx

Square both sides

sin^2x=cox^2x

sin^2x=1-sin^2x

2sin^2x=1

sin^2x=1/2

sinx=+ or - (1/sqrt(2))

45, 135, 225, 315 degrees

BUT what I would have done is

sinx=-cosx

-sinx/cosx=cosx/cosx

-tanx=1

tanx=-1

135, 315 degrees

I need someone to tell me why my thinking process would or would not work. Thanks!

EDIT: Similar question I need help with too

sinx-cosx=1

Here's my approach

(sinx)^2=(1+cosx)^2

sin^2x=1+2cosx+cos^2x

1-cos^2x=1+2cosx+cos^2x

0=2cosx+2cos^2x

0=2cosx(1+cosx)

cosx=0,-1

90, 180, 270 degrees

However 270 is not an answer

I feel like I understand the concept just not getting the same answers. Any help would be GREATLY appreciated