Question

sinx+sinx=0? is it 2sinx? or sin2x?

Answer 1

sinx+sinx=0
sinx=-sinx
sin(x)=sin(-x)
x=-x

Answer 2

x=-x
there is only one value that makes it true.

Answer 3

2sinx=sinx+sinx

if you mean that...

Answer 4

2sin x=0 implies sin x =0 implies x=integral multiple of pie

Answer 5

when will it equal to sin2x?

Answer 6

in what kind of situation?

Answer 7

sin 2 xis 2sinx cosx

Answer 8

no, 2sinx
sin(2x) is different
sin(2x)=sin(x)cos(x)+sin(x)cos(x)=2sin(x)cos(x)

Answer 9

oh ok , uhm another question... what are the solutions of this? 4cos2x=8sinxcosx

Answer 10

4cos(2x)=8sinxcosx
cos(2x)=2sinxcosx
cos(2x)=sin(2x)

Answer 11

integral multiple of pie is the solution that is npie, where n is an integer

Answer 12

2x=45
x=?

Answer 13

where did you get 45?

Answer 14

thanks princer and solomon

Answer 15

45 degrees is the only time when cosine and sine are equal.

Answer 16

so it is 45/2

Answer 17

the x is 45/2 I mean

Answer 18

what would happen in the sin2x=cos2x?

Answer 19

you will need to tell me first the angle at which sin(a)=cos(a)

where a=2x

Answer 20

I think I have disconnected about 20 times for the past 10-15 minutes.

Answer 21

it's not indicated?

Answer 22

it's fine lol

Answer 23

the angle at which cos=sin is 45, so to make 2x =45, the x has to be 45/2.

Answer 24

so what would be the values?

Answer 25

your interval is (-infinity,+infinity)
or [0,360] or some other interval?

Answer 26

[0,360] is the interval

Answer 27

so, your solution will be pi/4

Answer 28

only pi/4?

Answer 29

or 135º

Answer 30

why 135? aren't there two functions?

Answer 31

my bad, 135 is not a solution, because cos(135) doesn't equal sin(135).

Answer 32

x should be 45.

Answer 33

no other coterminal angles, because the interval is [0,360] (only one round)

Answer 34

I mean 2x is 45

Answer 35

oh ok so entering the values unto sin/cos is for checking?

Answer 36

I think I should get a rest.. I am sorry.

Answer 37

it's fine. thanks btw