SOLUTION: 13. Find the exact value of sin 30 ° - sin 45 ° cos 45 ° . a. 0 b. 1/2 c. 1 d. 2 14. Find the value of tan 42 ° to 4 decimal places. a. 2.2914 b. 0.9004 c. 1.11

Algebra ->  Trigonometry-basics -> SOLUTION: 13. Find the exact value of sin 30 ° - sin 45 ° cos 45 ° . a. 0 b. 1/2 c. 1 d. 2 14. Find the value of tan 42 ° to 4 decimal places. a. 2.2914 b. 0.9004 c. 1.11      Log On


   

Question 57558:
13. Find the exact value of sin 30 ° - sin 45 ° cos 45 ° .
a. 0
b. 1/2
c. 1
d. 2

14. Find the value of tan 42 ° to 4 decimal places.
a. 2.2914
b. 0.9004
c. 1.1106
d. 0.7431

15. Find the value of sec 38 ° to 4 decimal places.
a. 1.6243
b. 0.7880
c. 0.6157
d. 1.2690


Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!

13. Find the exact value of sin 30 ° - sin 45 ° cos 45 ° .
highlight%28a%29. 0
b. 1/2
c. 1
d. 2
Here's how:
sin(30)=1/2, sin(45)=1%2Fsqrt%282%29, cos(45)=1%2Fsqrt%282%29, therefore,
1%2F2-%281%2Fsqrt%282%29%29%2A%281%2Fsqrt%282%29%29
1%2F2-1%2F2
0

14. Find the value of tan 42 ° to 4 decimal places.
a. 2.2914
highlight%28b%29. 0.9004 Make sure you calculator is on degree mode.
c. 1.1106
d. 0.7431

15. Find the value of sec 38 ° to 4 decimal places.
a. 1.6243
b. 0.7880
c. 0.6157
highlight%28d%29. 1.2690
sec(x)=1/cos(x), so if you have a ti-83 type in (cos(38))x%5E%28-1%29 and it will give you the reciprocal of cos(38) which is sec(38).
Happy Calculating!!!