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Calculați:
a) sin30° · tg45° + cos30° · ctg60°
b) sin60° · cos60° + sin30° · cos30° − sin45°· cos45°


Răspuns :

Răspuns:

Explicație pas cu pas:

a) sin30° · tg45° + cos30° · ctg60°=1/2×1+√3/2×√3/3=1/2+3/6=1/2+1/2=1

b) sin60° · cos60° + sin30° · cos30° − sin45°· cos45°=

=√3/2×√1/2+1/2×√3/2-√2/2×√2/2=2√3/4-2√2/2=√3/2-√2=(√3-2√2)/2