Question

if cos(2x-1)=sin(3x+6) then the value of x is? Explanation please

Answer 1

@jim_thompson5910

Answer 2

cos(2x-1)=sin(3x+6)


cos(2x-1)=cos(pi/2 - (3x+6))


cos(2x-1)=cos(pi/2 - 3x - 6)


arccos[ cos(2x-1) ] = arccos[ cos(pi/2 - 3x - 6) ]


2x-1 = pi/2 - 3x - 6


now solve for x

Answer 3

The pi/2 is confusing me, i can't solve for x with that there

Answer 4

ok let z = pi/2

Answer 5

2x-1 = pi/2 - 3x - 6

2x-1 = z - 3x - 6

now solve for x

Answer 6

when you're done, replace z with pi/2

Answer 7

is it pi/2-1?

Answer 8

2x-1 = z - 3x - 6

2x = z - 3x - 6+1

2x+3x = z - 6+1

5x = z - 5

x = z/5 - 5/5

x = z/5 - 1

x = (pi/2)/5 - 1

x = pi/10 - 1


So \[\Large x = \frac{\pi}{10} - 1\]

Answer 9

That isn't one of the choices though

Answer 10

what are your choices

Answer 11

the choices are -7, 7, 17, 35

Answer 12

does it say anything about rounding to the nearest whole number?

Answer 13

No, but after the parenthesis there are degree signs but i don't think that has any relevance

Answer 14

oh degrees, not radians

Answer 15

x = z/5 - 1

x = 90/5 - 1

x = 18 - 1

x = 17

Answer 16

oh so it did matter, sorry about that, but thank you, ill try to understand it now!

Answer 17

you're welcome