SOLUTION: Hello. Please help me solve this. Determine the formula with the correct sign for cos (x/2) if sec x=-5/3, 3pi less than or equal to x less than 7pi/2. I set up the equ

Question 949025: Hello.
Please help me solve this.
Determine the formula with the correct sign for cos (x/2) if sec x=-5/3, 3pi less than or equal to x less than 7pi/2.
I set up the equation:

I simplified that to get sqrt5/5.
Am I on the right track?
Thank you!
Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!
Correct track, up to showing the formula, the half-angle formula for cosine.
The cosine is . Quadrant 3, according to part of your description.

Because quadrant 3, cosine(x/2) is NEGATIVE.

The algebra to do is very elementary.

RATIONALIZE THE DENOMINATOR.

RELATED QUESTIONS
Please help me with this problem. Thank You! Graph the function. f(x)= 4x+2, if... (answered by jim_thompson5910)

if cos thetha equals -3/5 with pi less than thetha less than 3pi/2 find the value of... (answered by Alan3354)

Please help me solve this: Find x where 0 is less than or equal to x is less than or... (answered by Fombitz)

Hello-Please help! I am just not grasping the concept of functions. Find the... (answered by jim_thompson5910)

The answer that I have come up with is: (e -1).2: The problem is what are the exact... (answered by jim_thompson5910)

Hello,Can you please help me solve this problem: 1.Solve the following equation for x... (answered by Edwin McCravy)

5(x+3)+9<=3(X-2)+6 Please help me to solve, I do not understand the procedure. the sign... (answered by stanbon)

Simplify the expression by using a double-angle formula. cos^2 (3pi/11) - sin^2... (answered by lwsshak3)

please help me solve this problem verify identities cos^2(x) cos(x) ------ (answered by stanbon)