Answer:
<em>Grades to be scored in 3rd exam = 88</em>
Step-by-step explanation:
Given that average of 3 numbers is 85.
First two numbers are 81 and 86.
To find:
3rd number so that average is 85
Solution:
Let the third number =
Formula for average is:
Here, sum of numbers =
Total count of numbers = 3
<em>Grades to be scored in 3rd exam = 88</em>
Answer:
Step-by-step explanation:
Triangle DEF is a right angle triangle.
From the given right angle triangle,
DE represents the hypotenuse of the right angle triangle.
With ∠E as the reference angle,
EF represents the adjacent side of the right angle triangle.
DF represents the opposite side of the right angle triangle.
To determine EF, we would apply
trigonometric ratio
Cos θ = opposite side/hypotenuse. Therefore,
Cos 49 = EF/8
EF = 8Cos49 = 8 × 0.6561
EF = 5.2488
Rounding to the nearest tenth, it becomes 5.2
Question 1:
<h3>Answer: The number does <u>not</u> change</h3>
Removing the zero from 0.76 leads to .76 which is the same as before. Both lead to in scientific notation.
Personally I prefer the zero up front to make the decimal point stand out easier. Of course it's just a preference, so its up to you to decide which you prefer.
===========================================
Question 2:
<h3>Answer: Yes the number changes</h3>
Taking the zero out of 10.25 leads to 1.25 which is definitely a different number (and smaller). Therefore, this zero is a significant digit compared to before.
Answer:
x = pi/2 + 2 pi n x = pi + 2 pi n where n is an integer
x = 5pi /3 + 2 pi n
Step-by-step explanation:
8 cos^2 x + 4 cos x-4 = 0
Divide by 4
2 cos^2 x + cos x-1 = 0
Let u = cos x
2 u^2 +u -1 =0
Factor
(2u -1) ( u+1) = 0
Using the zero product property
2u-1 =0 u+1 =0
u = 1/2 u = -1
Substitute cosx for u
cos x = 1/2 cos x = -1
Take the inverse cos on each side
cos ^-1(cos x) = cos ^-1(1/2) cos ^-1( cos x) =cos ^-1( -1)
x = pi/2 + 2 pi n x = pi + 2 pi n where n is an integer
x = 5pi /3 + 2 pi n