suma i różnica fcji trygo.

[elvisomadzia]

\(\displaystyle{ (cos15 ^{o}+sin15 ^{o})(cos15 ^{o}-cos75 ^{o})}\)

[Dakurels]

\(\displaystyle{ (cos15 ^{o}+sin15 ^{o})(cos15 ^{o}-cos75 ^{o})}\)
\(\displaystyle{ (cos15 ^{o}+sin15 ^{o})(cos15 ^{o}-sin15 ^{o})}\)
\(\displaystyle{ cos^215^o-sin^215^o}\)

[elvisomadzia]

Tjaaa w tym sęk, że i ja do tego doszłam, but what now?

[Dakurels]

\(\displaystyle{ sin^2 \alpha = 1-cos^2 \alpha}\)
\(\displaystyle{ cos^215^o-sin^215^o=2cos^215^o-1=cos30^o= \frac{\sqrt{3}}{2}}\)