Answer:
x=πn, n∈Z
Step-by-step explanation:
if sin²2x=1-cos²2x, then
1-cos²2x-2cos2x+2=0; ⇒ cos²2x+2cos2x-3=0; ⇔ (cos2x+3)(cos2x-1)=0;

Answer:
A
Step-by-step explanation:
edgenuity
Answer:
160°
Step-by-step explanation:
-Given the angle in radians as 
-We know that 
-Let our angle theta be X
#We therefore equate and cross multiply:

Hence, angle θ is 160°
Answer:
C. Many of the people selected to participate in the survey who do not respond might have opinions different from those who do respond.
Step-by-step explanation:
The survey is said to be biased by non-response survey if many people did not respond to the survey this might be much affected the result of survey.
The reason that people might be refuse to participate in the survey that survey may include any embarrassing information, illegal activities or personal details so many people did not respond to the survey. Also these peoples has different opinion from other peoples who respond in the survey. Thus this cause biased.
Answer:
New avaerage if 2 students (15 year old) left = 13
Step-by-step explanation:
Given:
Average age of 20 students = 13.2
Find:
New avaerage if 2 students (15 year old) left
Computtaion:
Sum of all 20 student's age = 20 x 13.2
Sum of all 20 student's age = 264
Sum of current 18 student's age = 264 - 15 - 15
Sum of current 18 student's age = 234
New avaerage if 2 students (15 year old) left = 234 / 18
New avaerage if 2 students (15 year old) left = 13