How do you solve sin^2x-1=0 and find all exact general solutions?

1 Answer
Feb 8, 2017

x = (n-1/2)pi or (2 n-1)pi/2

Explanation:

sin^2 x-1=0

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

sin x -1 =0, sin x =1, x= 1/2 pi, 5/2 pi,...

sin x + 1 =0, sin x =-1, x= 3/2 pi, 7/2 pi,...

we can say that,

x = 1/2 pi, 3/2 pi,5/2 pi, 7/2 pi,...

we can use arithmetic progression to solve this sequence where,

a=1/2 pi, d =pi.

T_n = 1/2 pi+(n-1)pi =(1/2+n-1)pi

T_n =(n-1/2)pi or (2 n-1)pi/2

Therefore it general solution for x is (n-1/2)pi or (2 n-1)pi/2 for all n