
Recall the half-angle identity:

So in order to find

, we only need to know the value of

. But there are two possible values. To decide which to take, we use the given information: we know that

lies in quadrant III, which means

, so

, which places

in quadrant II. In this quadrant, the sine of angle is positive, and so


is an angle of a ray whose terminal point,

lies on the circle

. The

-coordinate is all we need to know in order to find that

. So,
Step-by-step explanation:
= 4x( x -1) -7( x-1)
= 4x^2 -4x -7x +7
= 4x^2 -11x +7
Answer:
f(x)=19(2)^x
Standard form of exponential graph is f(x) = ab^x
Plugging in (0, 19), you get
19 = ab^0 -> 19 = a(1)
a=19
f(x)=19b^x
1216 = 19(b)^6
64=b^6
b=2
-> f(x) = 19(2)^x
15/8 when solved it is that