# C4 TrigonometryWatch

#1
i've been staring at this question for the past two hours with no luck, so i have finally resigned to TSR!
I know what the answer is, but an explanation would be great.
Much thanks

Solve the equation 2sin2(feta) + 3cos2(feta) = 1 for 0-360

I managed to rearrange the equation into rsin(2(feta)+(alpha)) but got no further..
0
9 years ago
#2
If you did it correctly than

rsin(2(theta)+(alpha)) =1

=> sin(2(theta)+(alpha)) = 1/r

=> 2theta + alpha = arcsin(1/r)
0
9 years ago
#3
**** i couldnt do that question and i got it on monday
0
9 years ago
#4
feta?
0
9 years ago
#5
(Original post by miml)
feta?
They meant theta of course...
0
#6
By solve the equation it meant find the roots from the graph. Which i for some reason was unable to do.
0
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