SOLUTION: Suppose sin x = 1/7
cos x > 0, sin y = −2/5
and cos y < 0. Then
cos x =
cos y =
Find each of the following quantities:
sin(x + y) =
cos(x + y) =
tan(x + y) =
Algebra ->
Trigonometry-basics
-> SOLUTION: Suppose sin x = 1/7
cos x > 0, sin y = −2/5
and cos y < 0. Then
cos x =
cos y =
Find each of the following quantities:
sin(x + y) =
cos(x + y) =
tan(x + y) =
Log On
Question 923637: Suppose sin x = 1/7
cos x > 0, sin y = −2/5
and cos y < 0. Then
cos x =
cos y =
Find each of the following quantities:
sin(x + y) =
cos(x + y) =
tan(x + y) = Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Suppose sin x = 1/7 cos x > 0,
Note: cos(x) = sqrt(49-1)/7 = sqrt(48)/7
-----------------------------------------------
sin y = −2/5 and cos y < 0.
Note: cos(y) = -sqrt(25-4)/5 = -sqrt(21)/5
------------------------------
Then
cos x = 4sqrt(3)/7
cos y = -sqrt(21)/5
----------------------------
Find each of the following quantities:
sin(x + y) = sin(x)cos(y)+cos(x)sin(y)
Substitute to get the numerical answer.
-----
cos(x + y) = cos(x)cos(y)-sin(x)sin(y)
Substitute::
tan(x + y) =
Divide sin(x+y) by cos(x+y)
==================================
Cheers,
Stan H.
===============
(