4 sin^2 θ + 13cos^2 θ = 7
sin^2 θ = 1 - cos^ θ
4 - 4cos^2 θ + 13cos^2 θ = 7
9cos^2 θ = 3
cos^2 θ = 1/3
cos θ = # (1/3) # - square root
Square root of (1/3) has +1/3 and -1/3 as values of cos
Find the key angle by doing the cos inverse of #1/3
K.A = cos^-1 #(1/3) = 0.955
θ lies in all 4 quadrants
The values of θ are:
θ = 0.955, 2.186, 4.096, 7.23
Ignore 0.955, 2.186, 4.096, 7.23 as they are out of range pi/2 = 1.571
The the value of θ = 0.955 = 0.96 (to 2 d.p) radian
Hope it helped!
Answer:
1. -7
2. 212
3. -49
4.-1,991
5. 78
6. -16
7. 2
8. 100
9. 16
10. 16
11. 13
12. 75
13. |12| = 12
14.|12| = 12
15. |8|
16.| 10|
17.15
18. 1,400
Step-by-step explanation:
Answer:
0.2 = 2/9
Step-by-step explanation:
Hope my answer has helped you!
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<span>A = 4.7 + C
where A represents the students who got A's, and C is the number of hours that the C-grade students spent on homework per week</span>
