Question

найдите значение cosa a если известно, что sina = - 4/5 

Answer 1

cosa = корень(1-sin^2a) = корень(1-(4/5)^2) = корень(1-16/25) = корень(9/25) =3/5 = 0,6

Answer 2

 $cos^{2}x =1- sin^{2} x = 1-frac{-4}{5} = 0.36$

$cosx = sqrt 0.36$</var></p> <p><var></var><img src=[/tex]cosx = 0.6" title="cosx = sqrt 0.36 " title="cosx = 0.6" title="cosx = sqrt 0.36 " alt="cosx = 0.6" title="cosx = sqrt 0.36 " />

$cosx = sqrt 0.36$

[tex]cosx = 0.6" />