sin(3)+cos(3)sin(3)tan(3)3=0=−cos(3)=−1=−4+,∈ℤ=−12+3
sin(3x)+cos(3x) =0 sin(3x) =−cos(3x) tan(3x) =−1 3x =−
π
4
+kπ,k∈
Z
x =−
π
12
+
k
π
3
Since −<<
−
π
<
x
<
π
, −2≤≤3
−
2
≤
k
≤
3
. Thus, the solution set is
{−34,−512,−12,4,712,1112}
Answer: 8400 $
Explanation:
His original debt: money paid for 10 months + remaining debt
Assume X is his original debt
Then X= 10 • 150 + 6900
X= 1500+6900=8400$
1) 58
2) 624669
3) 400
4) 258615
5)444542
6)12792
7) 628524
8) 119952
9) 445784
10) 314106
11) 97908
