Answer:
Lower limit = 1007.95 cm/s
Upper limit = 1142.05 cm/s
Step-by-step explanation:
We have to calculate a 95% CI with population's standard deviation known.
The sample is size n=60, with mean M=1075.
The confidence interval can be expressed as:

For a 95% CI, the value of z=1.96.

Hello
cos ( x + pi/2) =cos(x)cos(pi/2)-sin(x) sin(pi/2)
= cos(x)×0-sin(x) ×1
cos ( x + pi/2) = - sin(x)
Well u do 31.2 x 18 which is 561.6 then u divide by 2 because the formula for a triangle is base x height divided by 2 so It is 280.8
The answer is C
just factor every option and you will find the answer