SOLUTION: Need help with question please; Given; sin (x+y) = sin x cos y+ cos x sin y and cos (x +y) =cos x cos y - sin x sin y. Solve algebraically ; cos (x+90degrees) = 2 sin ^2 x - pi/2
Algebra.Com
Question 984824: Need help with question please; Given; sin (x+y) = sin x cos y+ cos x sin y and cos (x +y) =cos x cos y - sin x sin y. Solve algebraically ; cos (x+90degrees) = 2 sin ^2 x - pi/2 < x < pi/2.
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
You should get used to using radians instead of degrees. 
\ =\ 2\sin^2x)
\ =\ 2\sin^2x)
\ =\ -\frac{1}{2})
Use the unit circle to find the angle whose sine is negative 1/2 in the given interval. Negative angles are measured clockwise from the positive x-axis.
John
My calculator said it, I believe it, that settles it
RELATED QUESTIONS
Can you help me please ;Given; sin (x+y) = sin x cos y + cos x sin y and cos (× + y)= (answered by Boreal,solver91311)
Can you help me please; Given sin (x+y) = sin x cos y + cos x sin y and cos (x+y) =... (answered by Alan3354)
Can you help battle with this; Given ; sin(x+y) = sin x cos y +cos x sin y and cos... (answered by Alan3354)
Simplify cos(x)cos(y) +... (answered by Edwin McCravy)
Verify the identity.
(cos(x) - cos(y))/(sin(x) + sin(y)) + (sin(x) - sin(y))/(cos(x) + (answered by solver91311)
Simplify... (answered by addingup)
Given sin (x+y)= sin x cos y + cos x sin y
and cos(x+y) = cos x cos y -sin x sin y... (answered by Alan3354)
sin(x+y)=sin(x)cos(y)+sin(y)cos(x)
20 sin(x)+21... (answered by Edwin McCravy)
Given sin (x+y)= sin x cos y + cos x sin y
and cos(x+y) = cos x cos y - sin x sin y... (answered by Alan3354)