Write cos(-83degrees) as a function of a positive angle
Prove that tan^2(alpha)-1+cos^2(alpha)=tan^2(alpha)sin^2(alpha)
since cos(-x) = cos(x), what do you think?
cos(-x) = cos(0-x)
= cos0*cosx - sin0*sinx
= 1*cosx - 0
= cos(x)
Prove that tan^2(alpha)-1+cos^2(alpha)=tan^2(alpha)sin^2(alpha)
cos(-x) = cos(0-x)
= cos0*cosx - sin0*sinx
= 1*cosx - 0
= cos(x)