A few days ago
Rainey B

Trig—How do I solve for angle measure x?

I need to solve for x for both of these equations.

sin(x)- (square root of 3)cos(x) = 1

and

3(-cos(x)) = sin^2(x)

help please?

Top 1 Answers
A few days ago
Anonymous

Favorite Answer

sin(x) – sqrt(3)cos(x) = 1

Divide by sqrt(1 + 3) = 2:

(1/2)sin(x) – (sqrt(3)/2)cos(x) = 1/2

cos(pi/3)sin(x) – sin(pi/3)cos(x)= 1/2

sin(x – pi/3) = 1/2

sin(x – pi/3) = sin(pi/6)

x – pi/3 = 2n pi + pi/6 or x = 2n pi + 5pi/6 for any integer n

x = 2n pi + pi/2

or

x = 2n pi + 7pi/6.

-3cos(x) = sin^2(x)

– 3cos(x) = 1 – cos^2(x)

cos^2(x) – 3cos(x) – 1 = 0

cos(x) = ( 3 +/- sqrt(9 + 4) ) / 2

cos(x) = (3 +/- sqrt(13) ) / 2

As (3 + sqrt(13) ) / 2 > 1,

x = 2n pi +/- arccos( (3 – sqrt(13)) / 2 ) for any integer n.

1