All categories

4 years ago

Solve the equation: Sin2x - Sinx = 0

1 answer:

5 0

We know that sin2x=2sinxcosx
(search the net for proof if you wish)

So the original equation becomes

2sinxcosx-sinx=0
The two terms both have sinx that can be taken out to get:

sinx(2cosx-1)=0
This is true if sinx=0 or 2cosx-1=0 , rewritten: cosx=1/2

sinx=0 than x=2kπ
cosx=1/2 than x=π/3+2kπ
where k is an integer

You might be interested in

-4x + 8 > 12 inequality solution ?

BARSIC [14]

Answer:

x<-1

Step-by-step explanation:

-4x+8>12

-4x>12-8

-4x>4

x>4/-4

x>-1

x<-1

6 0

3 years ago

Can someone please help me with this question please ?

EleoNora [17]

Answer:

x=43

Step-by-step explanation:

Since the lines are parrallel, the angle underneath the one you are finding is equal to 65. To find the total value of (x+72) you subtract 65 from 180, giving you 115.

x+72 = 115

then you subtract 72 from both sides

x=43

8 0

4 years ago

0.0176165803 is estimated to what

bezimeni [28]

It most common to round to the hundredths place, this is two spaces after the decimal.

So look two spaces right - 0.17. If the third digit (in this case 6) is higher than 5 you round the number up if its not, keep it the same.

"6" is greater than five, so round it to about (or approximately) 0.18.

5 0

3 years ago

The straight line with equation y=3/4x makes an acute angle theta with the x-axis.

yanalaym [24]

The angle is arctan(3/4) => sin(2t) = sin(2arctan(3/4)) =
2sin(arctan(3/4))cos(arctan(3/4))

Let z = arctan(3/4) => tan(z) = 3/4

2sin(arctan(3/4))cos(arctan(3/4)) = 2sin(z)cos(z) = 2(3/5)(4/5) = 24/25

<span>cos(2t) = cos^2(t) - sin^2(t) = cos^2(z) - sin^2(z) = (4/5)^2 - (3/5)^2 = (16 - 9)/25

= 7/25

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
</span>

7 0

3 years ago

Seven cards are drawn from an ordinary deck. In how many ways is it possible to draw (b) only 8's, 's and (c) no 's, 's an

elena-14-01-66 [18.8K]

Complete question :

Seven cards are drawn from an ordinary deck. In how mnat ways is it possible to draw (a) only 5s (b)only 8s, 9s, and 10s, (c) no 8s, 9s, and 10s (d) exactly 2 jacks or kings, (e) 5 spades and 2 hearts?

Answer:

0; 792 ; 100396 ; 30408224 ; 18643560 ;

Step-by-step explanation:

Number of cards in a deck = 52

Number of cards to be drawn = 7

Using combination:

nCr = n! ÷ (n-r)!r!

A.)

Number of 5's in a deck = 4

4C7 = 0

(B.)

only 8s, 9s, and 10s,

Number of 8, 9 and 10's = 4 *3 = 12

12C7 = 12! ÷ 5!7! = 792

(C)

no 8s, 9s, and 10s ;

Number of cards to select from = 52 - (3(4)) = 40C7 = 18643560

(D)

exactly 2 jacks or kings,

Number of jack or king in deck = 8 ; other 5 could be any of the rest : (52 - 8) = 44

8C2 * 44C5 = 28 * 1086008 = 30408224

(e) 5 spades and 2 hearts?

Number of spades = 13

Number of hearts = 13

13C5 * 13C2

1287 * 78 = 100396

4 0

3 years ago