Question 841499: given that 180 degrees is equal or less than theta is less than or equals to 360 degrees, find the exact sin theta if cos theta is (i) 0.7 (ii) -3/5
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! given that 180 degrees is equal or less than theta is less than or equals to 360 degrees,
Note: sin is negative in the interval 180<= t <=350
--------------------------------------------------------
find the exact sin(t)
if cos (t) is
(i) 0.7
By definition, cos = x/r
Since cos(t) = 7/10, x = 7 and r = 10
The y = =sqrt[10^2-7^2] = -sqrt(51)
Your Problem:
sin(t) = -y/r = -sqrt(51)/10
==========================================
(ii) -3/5
If cos(t) = -3/5, x = -3 and r = 5
The y = -sqrt(5^2-3^2) = -sqrt(16) = -4
Your Problem:
sin(t) = y/r = -4/5
==========================================
Cheers,
Stan H.
==================
|
|
|
