Friday

April 18, 2014

April 18, 2014

Posted by **Kelly** on Monday, March 14, 2011 at 6:38pm.

2cos(x)-3=0

- Trig -
**bobpursley**, Monday, March 14, 2011 at 6:40pmIs this cosx=1/2sqrt3 ?

- Trig -
**Kelly**, Monday, March 14, 2011 at 6:42pmno it's 2cosx-sqrt3=0

- Trig -
**Reiny**, Monday, March 14, 2011 at 6:44pmI will read it as

2cosx - √3 = 0

cosx = √3/2

x = 30 , from the standard 30-60-90 triangle

or x = 330

"all solutions " would be

x = 30 + k(360) or x = 330+k(360) where k is an integer.

- Trig -
**Kelly**, Monday, March 14, 2011 at 7:06pmHow do you find the solutions?

- Trig -
**Reiny**, Monday, March 14, 2011 at 7:34pmsince the standard cosine curve has a period of 360, any answer you have will repeat itself in the next curve or 360 either to the right or to the left.

by multiplying 360 by k, k and integer, I am simply adding/or subtracting multiples of 360 to any answer.

to get my original 30, as I said, I recognized the rations of the 30-60-90 right-angled triangle, which are 1:√3:2.

Secondly , since the cosine is positive in the 1st and 4th quadrant, the 30 will be the 1st quadrant solution and 360-30 or 330 would be the 4th quadrant solution.

**Related Questions**

trig - how can i find all the exact solutions to the equation : 2cos^2x + 3sinx...

trig - Find all solutions in the interval [0,360) sin(4t)=3/2

trig - Find all solutions to the equation 2cos(2x) = x + 1, correct to 4 ...

RADICAL EXPRESSIONS/ALGEBRA 2 - Hi. I pretty much have the answer for these ...

Trig - 2cos^2Beta-Cosbeta=0 (find all solutions for the equation in the interval...

trig - find the general solutions to the equations: 1) sec x = -2 2) 2 sin^2 x...

trig - Find the solutions to the equation cos2x=sinx and 2cos^2x-3cosx-3=0

trig - findall exact solutions ( in terms of radians) to the equation 2cos(40)-...

trig - The average depth of water at the end of a dock is 6 ft. This varies 2 ft...

trig - find the exact solutions ( in degrees) sin^2+2cos=-2 range= 0ܦ&...