# Math Help - trig equation

1. ## trig equation

I have no idea how to solve an equation
-1.2sin2t+0.8cost=0.8
(tried all trig formulas and substitution method)
If anybody could help?
Thanks.

2. Originally Posted by Romanka
I have no idea how to solve an equation
-1.2sin2t+0.8cost=0.8
(tried all trig formulas and substitution method)
Is the first term -1.2 sin(2t) or -1.2 sin^2(t)?

Thank you!

3. -1.2sin(2t)+0.8cost=0.8

4. Originally Posted by Romanka
-1.2sin(2t)+0.8cost=0.8
sin(2t) = 2sin(t)cos(t)

Multiply that by -1.2 and factor out cos(t). Then solve using both cos and sin

5. I tried all these steps, but there is 0.8 in the right side.
I have
3sintcost-cost+1=0 and can't solve it