When two or more sinusoidal quantities are added or subtracted, what sinusoidal quantities must they be RT

When two or more sinusoidal quantities are added or subtracted, what sinusoidal quantities must they be RT

Of the same frequency

Is it right to say that phasor is equal to sine? Can we use the equal sign between the analytic formula of sine and phasor formula?

Phasor can be used to represent sinusoidal quantity, but phasor is not sinusoidal quantity. Therefore, the analytic formula of sinusoidal quantity and phasor formula cannot be equal. They are not equivalent

2. Write the sine expression of phasor 220 ∠ 30 ° u = how much?

U = 220 * radical 2 * (sinwt + 30 degrees) V

Function expression, sine function! Thank you!
The maximum value is 1 / 2, the period is 2 π / 3, and the initial phase is π / 6. Find the expression of this sine function. Thank you!

The period is 2 π / 3, so ω = 3, the initial phase is π / 6, and the maximum is 1 / 2
The expression of sine function is y = 1 / 2Sin (3x + π / 6)

As shown in the figure, in the trapezoidal ABCD, ad ‖ BC, ∠ ABC = 90 °, ab = 20cm, CD = 25cm. The moving points P and Q start from point a at the same time: point P moves along the route of a {D} C at the speed of 3cm / s, point Q moves along the route of a {B} C at the speed of 4cm / s, and P and Q arrive at point C at the same time (1) Find the area of trapezoid ABCD; (2) let P and Q move in t (seconds), and the area of quadrilateral apcq is s (cm2), try to find the functional relationship between S and T, and write out the value range of independent variable t; (3) under the condition of (2), is there such a t that the area of quadrilateral apcq is exactly 25 times that of trapezoid ABCD? If it exists, find the value of T; if not, explain the reason

(1) In RT △ Dec, according to Pythagorean theorem, EC = 15cm. From the meaning of the title, AD + DC3 = AB + be + EC4, AD + 253 = 20 + AD + 154. The solution is ad = 5. The area of trapezoidal ABCD = (AD + BC) × AB2 = (5 + 20) × 202 = 250 (cm2) (...)

What is 1874 divided by 9 divided by 10 multiplied by one in two to the ninth power of plus 5 minus 7 plus 10

2544586

Application of scale in Grade 6 of primary school
On a map with a scale of 3000000th, the distance between a and B is 4.5cm. How many hours can a car reach from a to B at the speed of 60km / h?

Distance between the two places: 4.5 ÷ 1 / 3000000 = 13500000 (CM)
＝135(km)
Time: 135 △ 60 = 2.25 (hours)
A: 2.25 hours

Draw a rectangle with the ratio of length to width of 5:3 on paper with a scale of 1 / 500, and the circumference of the rectangle is 32 cm
What is the actual square meter of this rectangular land

Actual perimeter = 32 * 500 = 16000cm = 160m
L + W = 160 / 2 = 80m
Length = 80 ÷ (5 + 3) × 5 = 50m
Width = 80-50 = 30m
Actual area = 50 * 30 = 1500 square meters

Use the rounding method to get the approximate number
(1) 0056 (. Accurate to 0.01);
(2) 386 (. To the tenth);
(3) 2013 (. Accurate to 100 digits);
(4) 56732 (. Accurate to the thousandth);

1.3.01
2.9.4
three point two zero zero zero
4.0.567
That's right

There is a railway bridge with a length of 1000 meters. A train passes through the bridge. It takes 120 seconds for the train to get on the bridge and get off the bridge completely. The time for the whole train to be completely on the bridge is 80 seconds. What are the speed and length of the train?

Let the speed of the train be x m / s and the length of the train body be y m, and the relationship between them is listed. The equations are 120x = 1000 + y, ①, 80x = 1000-y, ②, which are solved by ① and ②: x = 10 m, y = 200 m. a: the speed and length of the train are 10 m / s and 200 m respectively