Question

oblicz a-b ,gdy dla a=60 stopni

Answer 1

a-b=(sin⁴α-cos⁴α)-(1-4sin²xcos²x)=(sin²α-cos²α)(sin²α+cos²α)-1+4sin²xcos²x=

=(sin²α-cos²α)(1)-1+4sin²xcos²x=

=sin²α-cos²α-1+4sin²xcos²x=sin²α-cos²α-sin²α-cos²α+4sin²xcos²x=

=-2cos²α+4sin²xcos²x=-2*¼+4sin²xcos²x=-½+4sin²xcos²x

 

α=60°

cos60°=½

cos²60°=¼

 

chyba ze jest zle napisane i b=1-4sin²αcos²α

to wtedy

a-b=-½+4sin²αcos²α=...

sin60=√3:2

...=-½+4*(3/4)*(1/4)=-½+¾=¼