Question

sa se calculeze sin la 2 55 grade+ sin la2 35 grade

Answer 1

[tex]\sin^2 55^o + \sin^2 35^o = \sin^255^o+\sin^2(90^o-55^o) = \\ = \sin^2 55^o+ \big[sin(90^o-55^o)\big]^2 = \sin^2 55^o + \big(\cos55^o\big)^\bi2 = \\ =\sin^255^o+\cos^255^o = 1 \\ \\ \\ $M-am folosit de relatiile: \left| \begin{array}{c} \sin(90^o-x)= \cos x$ $ $ $ \\ \sin^2x + \cos^2 x = 1$ $ $ $ $ $ $ $ \\ \sin^2 x = (\sin x)^2\quad \quad $ $ \\ \cos^2x = (\cos x)^2\quad $ $ $ $ $ $$ \end{array} \right[/tex]