Help me please
3.2sin2x=2+cosx in the interval [0,2pi]
4. tan3x(tanx-1)=0
5.2sin^2x+3sinx+1 in the interval [0,2pi}

Question

Help me please
3.2sin2x=2+cosx in the interval [0,2pi] 
4. tan3x(tanx-1)=0
5.2sin^2x+3sinx+1 in the interval [0,2pi}

anonymous · Answer

OUCH! These take long haha ill take just one! Which one you want...the most? Lol

anonymous · Answer

i need all, but i will take the first one .

anonymous · Answer

Alrighty then you have:
$$\eqalign{
&5\cos(x)=\sqrt{3}+3\cos(x);x\in[0,2\pi] \
&2\cos(x)=\sqrt{3} \
&\cos(x)=\frac{\sqrt{3}}{2}
}$$
Now according to the CAST rule (let me know if you haven't learned that yet), cosin is positive in the first and fourth quadrants. By the way, do you want this in radians or degrees?

anonymous · Answer

radians

myininaya · Answer

You can use the unit circle to find when cos is sqrt(3)/2 @JustTooMuchh

myininaya · Answer

http://www.google.com/imgres?imgurl=http://www.sciencedigest.org/UnitCircle.gif&imgrefurl=http://www.sciencedigest.org/unit%2520circle.htm&h=575&w=732&sz=52&tbnid=b6OyxY_TLZ5-KM:&tbnh=92&tbnw=117&zoom=1&usg=__dtjqDbcHHHnWqqIWytwPhar-Xuo=&docid=d6VR7E5XbmcHeM&sa=X&ei=YphmUuCHIoqf2QX2wYCoBQ&ved=0CDoQ9QEwAw

myininaya · Answer

Use that circle to find when the x-coordinate is sqrt(3)/2

anonymous · Answer

k thanks