Step-by-step explanation:
We know that tan=sin/cos, so tan(x+π/2)=

Then, we know that sin(u+v)=sin(u)cos(v)+cos(u)sin(v),
so our equation is then
Then, cos(u+v)=cos(u)cos(v)-sin(u)sin(v), so our expression is then

2x-y=6;5x+10y=-10. -y=-2x+6. -y/-1=-2x+6/-1. y=2x-6. 5x+10y=-10. 5x+10(2x-6)=-10. 25x-60=-10. 25x=50. 25x/25=50/25. y=2x-6. y=(2)(2)-6. y=-2. Therefore, x=2 and y=-2
Step-by-step explanation:
using trig, tangent is equal to opposite over adjacent.
in this case, the angle is 45, opposite is 7, and adjacent is a.
thus tan 45° = 7/a
solve for a to get a = 7/tan 45° = 4.32
Pretty sure the answer is A