Răspuns:
Explicație pas cu pas:
1a)
sin²17°+cos²17°=1
b)sin²23°+cos²23°=1
c) sin²56°-sin²56°=0
d_tg47°×ctg47°=1
e) tg53°×tg 37°=ctg 37°×tg 37°=1
f)cgt42°×tg(90-48°)=ctg 42°×tg 42°=1
2
a) (1/2+1)x√3=3√3/2
b)√3/2×√3/3-1/2=1/2-1/2=0
c)√2/2×√2/2+1/2=1/2+1/2=1
e) 1-1=0
f)(1+1)x=4