The error is in step 2. if you are performing an operation on one side of the equation, it must be performed on the entire expression. you can’t only divide by 2 on one term, you must do it to everything in the equation. instead, you could add 6 to both sides first, giving you 2x = -4. Then you can divide by 2 on both sides. the answer is -2.
Answer:
-24/5
Step-by-step explanation:
The solution to the problem is as follows:
cscx < 0 means 1/sinx < 0, or sinx < 0.
sinx = -3/5 because you're dealing with a 3-4-5 triangle, and we established
sinx is negative.
sin2x = 2sinxcosx = 2*-3/5*4/5 = -24/25
cos(2x) = cos^2(x) - sin^2(x) = 16/25 - 9/25 = 5/25 = 1/5
tan2x = sin2x / cos2x = -24/5
Measure of angle 8 is 135°
