How do you find the exact value of #sin30cos55-cos30sin55# using the sum and difference, double angle or half angle formulas?
1 Answer
Sep 22, 2016
Explanation:
Use #sin (a-b)=sin a cos b - cos a sin b and sin 3a = 3 sin a - 4
sin^3a#.
Using the first formula, the given expression reduces to
Using the second, this is related to
Solving this cubic equation in s, the exact value of the given
expression s can be obtained, in a complicated form, as found in
.http://intmstat.com/blog/2011/06/exact-values-sin-degrees.pdf