Question

Will give medal!! Please help!!

Find all solutions to the equation.

7 sin2x - 14 sin x + 2 = -5

Answer 1

@mathstudent55 please help! Its super fast

Answer 2

@dumbcow @LoveIt

Answer 3

treat it like a quadratic equation
\[7u^2-14u +2 = -5\]
solve for "u"
then
\[\sin x = u\]
solve for x using inverse sine
\[x = \sin^{-1} u\]

Answer 4

I'm not too good at math, still in pre-algebra :(

Answer 5

okay so would the next step be 7u^2−14u+7
u=1

Answer 6

@dumbcow

Answer 7

therefore sin x= 1 and to solve for x sin-1 (1) ?

Answer 8

good now plug u = 1 into inverse sine function

or think what angles make sine = 1

Answer 9

90°

Answer 10

correct

Answer 11

okay so is that it?

Answer 12

depends on the domain given, for 0<x<360 thats it, one solution, x = 90

If they want all (infinite) solutions, then just add multiples of 360 to answer
--> 90 + 360n

Answer 13

So my answer is just 90 + 360n (on the assumption they want infinite solutions)?

Answer 14

@dumbcow

Answer 15

yes

Answer 16

Thanks so much! You're a life saver! @dumbcow

Answer 17

your welcome :)