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:
Step-by-step explanation:
(x-1)²+(y-2)² =4 compare the given equation with the general one
(x-h)² +(y-k)² =r², where (h, k) are coordinates of the center and r is radius
so center is at ( 1, 2) and radius is 2
The value of the digit in the tens place is 100 times as much as the value of the digit in the thousands place.
The first step would be to add 7 to both sides.
3n-7=30
add 7
3n=37
divide by 3
n=12.33
