Question

4cos^(2)θ+4sinθ=1 for 0°≤θ≤360°.

i got 30 and 150. why wrong?
@hartnn

Answer 1

how ?

Answer 2

what?

Answer 3

i mean how u got 30 and 150 ?

Answer 4

4(1-sin^(2)θ)+4sinθ=1
4-4sin^(2)θ+4sinθ=1
-4sin^(2)θ+4sinθ+3=0
sinθ=-1/2 or 1.5(rej)

sinθ=-1/2
θ=30, 150...

Answer 5

sin 30 is not -1/2
sin -30 is 1/2

Answer 6

or, sin (360-30) = -1/2

Answer 7

sin 30 is just +1/2

Answer 8

same for 150

Answer 9

oops

Answer 10

so, the solutions must be
360-30 and 360-150

Answer 11

thanks haha...

Answer 12

welcome ^_^
bye, gtg

Answer 13

gtg?

Answer 14

got to go

Answer 15

okok thank you a lot haha