The angle of elevation of x from y is 30° xy=40m, how height is x above the level of y​

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Describe the 2 algebraic methods you can use to find the zeros of the function f(t)=-16t^2+400.

17 in long 1.3 ft wide and 8in high what is the volume