Use Theorem s(x+y)= s(x)c(y)+c(x)s(y) to show
Then apply this formula to find the value of cos(/8)
Follow Math Help Forum on Facebook and Google+
Now apply the angle-sum identity for sine as required.
Then use: in the resulting formula. I would suggest letting to get a quadratic in . Take the appropriate root.
Last edited by MarkFL; November 13th 2012 at 10:00 PM.
View Tag Cloud