1/(sin(90 + θ)cos(360 - θ)) - tan²(-θ)
Note:
sin(90 + θ) = cosθ Cosine and Sine are complementary.
cos(360 - θ) = cosθ Cosine positive in 4th quadrant.
tan(-θ) = -tanθ Negative angle concept.
1/(sin(90 + θ)cos(360 - θ)) - tan²(-θ) = 1/(cosθcosθ) - (-tanθ)²
= 1/(cos²θ) - tan²θ
= (1/cosθ)² - tan²θ
Note: 1/cosθ = secθ
= (secθ)² - tan²θ
= sec²θ - tan²θ
= 1
Note that 1+ tan²θ = sec²θ is a Trigonometric identity.
That means: sec²θ - tan²θ = 1
Hope this explains it.
Answer:
2.25
step-by-step explanation:
multiplying .95 times 45 and subtracting it by 45
Answer:
3
Step-by-step explanation:
A + B is calculated by adding the same positions in both matrices.
and position (2, 3) in A+B is therefore the sum of position (2, 3) in A plus the position (2, 3) in B, which is then
-4 + 7 = 3
Answer:
We are 99% confident that the true mean of electricity comsumption is between (15.6 and 15.8) kWh
Step-by-step explanation:
Information provided
represent the sample mean for the usage of electricity
population mean (variable of interest)
represent the population standard deviation
n=1731 represent the sample size
Confidence interval
The confidence interval for the mean is given by the following formula if we know the population deviation:
(1)
The Confidence level provided is 0.99 or 95%, the value of significance is 
and 
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that 
And replacing we got:
We are 99% confident that the true mean of electricity comsumption is between (15.6 and 15.8) kWh
