<span>Anna learns in her science class that the human eye blinks an average of 4,200,000 times a year. What is this number expressed in scientific notation?</span>
Answer:
8x^2-1
Step-by-step explanation:
8x^2-x+4+x-5=8x^2-x+x+4-5=8x^2+4-5=8x^2-1
Answer:
Θ = 50°
Step-by-step explanation:
Using the cofunction identity
cosx = sin(90 - x)
Given
cos40° = sin(90 - 40)° = sin50° ⇒ Θ = 50°
sin θ = 3 / 7 = .429
sin^2 θ + cos^2 θ = 1 trig identity
9/49 + cos^2 θ = 1
cos^2 θ = 40 / 49 = .816 cos θ = .903
Check .429^2 + .903^2 = 1
cos .903 = 25.4 deg
In the second quadrant sin = +, cos = -, tan = -
So 25.4 deg in the second quadrant = 180 - 25.4 = 154.6 deg
Check:
sin 154.6 = .428
cos 154.6 = -.903
tan 154.6 = -.475
Answer:
Possible values of x are 50 < x < 110.
Step-by-step explanation:
Consider the perimeter of the field:
2x + 2(x + 30) < 500
2x + 2x + 60 < 500
4x < 440
x < 110.
Consider the area of the field:
x(x + 30 ) > 4000
x^2 + 30x - 4000 > 0
(x - 50)(x + 80) > 0
The critical values are x = -80 and 50.
As x is a width it must be positive so x > 50.
