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Rina8888 [55]
3 years ago
5

If 3 sinA+4 cosA=5 then prove that:sinA=3/5.​

Mathematics
1 answer:
lutik1710 [3]3 years ago
7 0

Answer:

Please check the explanation.

Step-by-step explanation:

Given the expression

3\:sinA+4\:cosA=5

\frac{4}{5}\:cosA=1-\frac{3}{5}sinA

Taking square on both sides

\left(\frac{4}{5}\:cosA\right)^2=\left(1-\frac{3}{5}sinA\right)^2

16\:Cos^2\:A\:=\:25\:+\:9\:Sin^2A\:-\:30\:Sin\:A

16\:-\:16\:Sin^2\:A\:=\:25\:+\:9\:Sin^2A\:-\:30\:Sin\:A

25\:Sin^2\:A\:\:-\:30\:Sin\:A\:+\:9\:=\:0

so the equation can further be easily solved

\sin \:A=\frac{3}{5}         ∵ sin A = [ 30 +- √(900 - 900) ] ÷ 50

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Which statement is true about the meaning of the equation 2=5x2/5
FinnZ [79.3K]
A:-) would be the correct answer because if 2/5 is 1/2 they size of 5 it would have to be 2/2-1/2.
5 0
3 years ago
Find each measurement indicated. Round your answer as the nearest tenth. HELP PLEASE!!!!!! URGENT
MaRussiya [10]

Answer:

(1) length AB = 21.0

(2) length BC = 45.0

Step-by-step explanation:

(1) To determine AB, apply Cosine rule;

|AB|^2 = |AC|^2 + |BC|^2 \ - \ 2[|AC| \times |BC]cos \ C\\\\|AB|^2 = 13^2 + 29^2 \ - \ 2(13 \times 29) cos(41)\\\\|AB|^2 = 1010 - 569.05\\\\|AB|^2 = 440.95\\\\|AB|= \sqrt{ 440.95} \\\\|AB| = 21.0

(2) To determine BC, also apply cosine rule;

|BC|^2 = |AB|^2 + |AC|^2 \ - \ 2[|AB| \times |AC]cos \ A\\\\|BC|^2 = 30^2 + 21^2 \ - \ 2(30 \times 21) cos(123)\\\\|BC|^2 = 1341 - (-686.245)\\\\|BC|^2 = 1341 + 686.245\\\\ |BC| = 2027.245\\\\|BC|= \sqrt{ 2027.245} \\\\|BC| = 45.0

8 0
3 years ago
What is the measure of the<br> third angle of this triangle?
Illusion [34]

Answer:

20 degrees

Step-by-step explanation:

every triangle had 3 angles that all add up to 180

the problem gives you two angles which are 120+40 which is 160

180-160 is 20 degrees which is whi it is the answer

3 0
2 years ago
Police can estimate the speed of a vehicle before the brakes are applied using the formula 0.75d=(s^2)/(30.25) where s is the sp
Kobotan [32]
150ft is 0.028 miles
So
(0.75x0.028)=(sxs) / 30.25
Meaning
(0.75x0.028)x 30.25 = (sxs)
And then square root to get the s
6 0
3 years ago
Read 2 more answers
(a) Derive an equation of the line passing through the points A(0, 545) and B(4, 726). (Let t be the independent variable and y
a_sh-v [17]

Answer:

The equation of the line is y=45.25t+545

Step-by-step explanation:

The general for of a line is:

y=mt+n       (1)

where:

m is the slope of the line and m is the intercept with the axis of the dependent variable, y in this case.

In order to obtain the value of the slope (m) we can use the corresponding slope formula:

m=\frac{y_{2}-y_1 }{t_2-t_1}         (2)

where t_1, t_2, y_1 and y_2 are the corresponding coordinates of the given points. In this case:

t_1=0\\t_2=4\\y_1=545\\y_2=726\\

Substituting these values in equation (2) we obtain:

m=\frac{726-545}{4-0}=\frac{181}{4}=45.25\\m=45.25

Hence, the line equation is now:

y=45.25t+n     (3)

Now to obtain the value of n you can follow two options:

  1. You can substitute one of your points, A or B, in equation (3). In this way, you will obtain an equation where the variable is n

Note that for this question, it is easier to select point A because of having the independent variable equals to zero t=0. Hence, substituting point A in equation (3):

45.25*0+n=545\\n=545

Therefore, the line equation is: y=45.25t+545

The second option to find n is to think of the meaning of the <em>intercept</em>. The <em>intercept </em>of a line is defined as the point in which the line crosses the axis of the dependent variable, which also means that the value of the independent variable for this point is zero. From this, we could have automatically said that n is equal to 545.

See the attachment for a plot of the line.

7 0
3 years ago
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