Simplify (sin^2)*(67.5deg) - (cos^2)*(67.5deg) and then evaluate exactly.

4 answers

well, cos 2x = cos^2 x - sin^2 x, so what do you think?

If you end up with 1/√2 you are correct.
How exactly do you get there though? I tried to follow a similar homework problem and got:

= (cos^2)*(67.5deg) - (sin^2)*(67.5deg)
= cos(2*67.5deg)
= cos135deg
= -√2/2
note that the problem was

sin^2(67.5)-cos^2(67.5)
= -cos(135)

my hint was not intended to make you forget what was originally asked. :-)

And, I know lots of folks hate roots in the denominator, but I see no reason why √2/2 is better than 1/√2. Just mt preference
Thank you very much!
Similar Questions
  1. solve the triangle.B=77.0deg b=13.95 a=20.6 I got A=38.5deg C=64.5deg c=34.55
    1. answers icon 1 answer
  2. Use a sum or difference identity to find the exact value.tan 25deg + tan 5deg / 1-tan 25deg tan 5deg
    1. answers icon 1 answer
    1. answers icon 1 answer
  3. A spherical ball is rolling down a slope with an inclination angle of 5deg.How do you calculate the Coefficient of the moment of
    1. answers icon 0 answers
more similar questions