solve for x sinx + sinx * cosx = 4?

Question

I tried dividing through by s. So we get

in x + in x * co x = 4/s

now multiply by both sides by the inverse of in x which is out x

1 + co x = 4 * out x / s

which leads to

co x = 4*out x / s - 1

co x = (out x +out x +out x +out x )/s - 1

co x = ( rfo x) / s - 1 (rfo = really far out)

now divide thur by o

cx = rfx/s - 1/o

cx = (rfxo - s) / so



take first derivitive

cso = rfo

such forth cs = rf

now factor into the mother equation....
cx = (rfxo - s) / so
which leads to
rfx= (rfxo-s)/o

what should i do from here? thank you fellow answerians :)

Answer 1

sinx is at most=1 and sin x* cos x = 1/2 sin (2x) is at most 1/2
so the sum could never be greater than 3/2.
No solution

Answer 2

If you graph it, you can find infinite number of solutions. Most likely you have to use numerical analysis to get all these solutions.

Answer 3

OMG. You should use trigonometric identities. That problem isn't algebra.