Sec= 1/(cos), you can add or subtract 360 degrees from any angle measurement without changing the value of any of the trig functions i.e. 405 degrees= 405-360=45. cos of 45 is sqrt(2)/2 so sec405= 2/sqrroot2
Answer:
cos 4u = co^s2 2u - sin^2 2u
Step-by-step explanation:
cos 4u = co^s2 2u - sin^2 2u
Let 4u = 2x
cos 2x = cos^2 x - sin^ 2 x
cos (x+x) = cos^2 x - sin^ 2 x
Using cos(x+y) = cos(x)cos(y) -sin(x)sin(y)
cos(x) cos(x)- sin(x) sin (x)= cos^2 x - sin^ 2 x
cos^2 (x) -sin^2 (x) =cos^2 x - sin^ 2 x
Since this is true
cos 2x = cos^2 x - sin^ 2 x
This is true
Substituting 4u back for 2x
cos 4u = co^s2 2u - sin^2 2u
This is true
She should use a computer to select 30 students at random then ask which ones play chess. The other options could produce more skewed results.
Answer:
1. -17 2. -20 3. -5 4. -1
