Question

find the sin(x+pi) in terms of x (HELP ME!!!!)

Answer 1

- sinx

Answer 2

what does that mean ?

Answer 3

can you walk me through it

Answer 4

that means angle lies in 3rd quadrant.

Answer 5

i still dnt get it how do i plug it in

Answer 6

is it sin(x=180) = -sinx

Answer 7

or am i way off

Answer 8

in 3rd quadrant sin ,cos,sec,cosec -ve but tan, cot +ve.

Answer 9

IM FREAKING LOST

Answer 10

using the trig identity
sin(a+b) = sin(a)cos(b) + cos(a)sin(b)

sin(x+pi) = sin(x)cos(pi)+ cos(x)sin(pi)
cos(pi) = -1
sin(pi) = 0

and you get
sin(x)(-1) + cos(x)(0)
= -sin(x)

Answer 11

sin(180+x)= -sinx
since sin is symmetrically opposite.