Answer: The speed is 105 miles/ hr and the direction of the train would be East if the girl is the frame of reference.
Step-by-step explanation:
Since we have given that
Speed of train = 100 miles per hour
Speed of girl = 5 miles per hour
Since the girl is moving towards the back of train.
So,it means train and girl are moving in opposite direction.
So, Relative speed would be
Hence, the speed is 105 miles/ hr and the direction of the train would be East if the girl is the frame of reference.
5. SSS
6. ASA
7. SAS
8. ASA
9. ASA
Answer:
x= -3
Step-by-step explanation:
Look at the screenshot, it explains how I got the answer.
Answer:
Here's what we know:
A = Lw (Area is length times width)
L = 2w + 6 (length is twice the width plus 6)
A = 140 (Area is 140 m2)
Plug in the variable values:
140 = w(2w + 6)
Distribute:
140 = 2w2 + 6w
Subtract 140:
2w2 + 6w - 140 = 0
Factor out a 2:
2(w2 + 3w - 70) = 0
Divide both sides by 2:
w2 + 3w - 70 = 0
(w + m)(w - n)
When we factor out the quadratic, we know it's going to be a +/- situation because the c value in the quadratic is negative, and the two numbers are going to be three away, the plus next to the 3 meaning that the larger number is going to be positive:
(w + 10)(w - 7) = 0
w = -10, 7
We can't have a negative length, so we can toss out the -10, leaving us with w = 7 meters.
L = 2 * 7 + 6
L = 14 + 6
L = 20
Check:
140 = 20 * 7
140 = 140
Answer:
(e) csc x − cot x − ln(1 + cos x) + C
(c) 0
Step-by-step explanation:
(e) ∫ (1 + sin x) / (1 + cos x) dx
Split the integral.
∫ 1 / (1 + cos x) dx + ∫ sin x / (1 + cos x) dx
Multiply top and bottom of first integral by the conjugate, 1 − cos x.
∫ (1 − cos x) / (1 − cos²x) dx + ∫ sin x / (1 + cos x) dx
Pythagorean identity.
∫ (1 − cos x) / (sin²x) dx + ∫ sin x / (1 + cos x) dx
Divide.
∫ (csc²x − cot x csc x) dx + ∫ sin x / (1 + cos x) dx
Integrate.
csc x − cot x − ln(1 + cos x) + C
(c) ∫₋₇⁷ erf(x) dx
= ∫₋₇⁰ erf(x) dx + ∫₀⁷ erf(x) dx
The error function is odd (erf(-x) = -erf(x)), so:
= -∫₀⁷ erf(x) dx + ∫₀⁷ erf(x) dx
= 0