trygonometria
Agata: wiedząc, że α jest kątem ostrym i tgα= 2, oblicz wartość wyrażenia 3cosα−2sinα.
15 lut 21:30
Eta:
| | a | | 2x | |
tgα=2= |
| = |
| , x >0, a= 2x b= x
|
| | b | | x | |
c
2=a
2+b
2 +. c
2= 5x
2 => c=
√5*x
| | a | | 2x | | 2 | | 2√5 | |
sinα= |
| = |
| = |
| = |
|
|
| | c | | √5*x | | √5 | | 5 | |
| | b | | x | | 1 | | √5 | |
cosα= |
| = |
| = |
| = |
|
|
| | c | | √5*x | | √5 | | 5 | |
podstaw i policz wartość
3cosα− 2sinα=........
15 lut 22:25