trygonometria
Olaa: wykaż że jeśli α jest kątem ostrym i 2cos2α+5sin2α=4, to (tgα+ctgα)2=4,5
18 mar 19:02
Olaa: bardzo prosze o pomoc
18 mar 19:10
Olaa: bardzo prosze o pomoc
18 mar 19:10
Olaa: bardzo prosze o pomoc
18 mar 19:11
ICSP: :(
| | 2 | | 1 | |
2cos2α + 5sin2α = 4 ⇒ 3sin2α = 2 ⇒ sin2α = |
| ⇒ cos2α = |
| |
| | 3 | | 3 | |
| | sin2x | | cos2x | |
(tgx + ctgx)2 = tg2x + 2 + ctg2x = |
| + 2 + |
| = |
| | cos2x | | sin2x | |
| | 2 | | 3 | | 1 | | 3 | | 1 | |
= |
| * |
| + 2 + |
| * |
| = 2 + 2 + |
| = 4,5 |
| | 3 | | 1 | | 3 | | 2 | | 2 | |
c.n.w.
18 mar 19:16