Trigonometry Help: Solving cos^2x = 2cosxsinx for x in the Range of 0 to 360

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To solve the equation cos^2x = 2cosxsinx for x in the range of 0 to 360 degrees, the first step is to rearrange the equation into a factored form: cosx(cosx - 2sinx) = 0. This leads to two possible solutions: cosx = 0 or tanx = 1/2. The discussion emphasizes understanding the factoring process, which is similar to solving a quadratic equation. The final goal is to find four angles that satisfy the original equation. The participants express gratitude for the clarification and successfully grasp the solution method.
Maria
Can someone help me with this:cos^2x = 2cosxsinx?
X E 0,360..
I really haven`t understood this trigonomy stuff yet..
 
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Did you see that sticky about posting homework?

Hint: forget trig for now, and simplify


a^2=ab.
 
Maria said:
Can someone help me with this:cos^2x = 2cosxsinx?
X E 0,360..
I really haven`t understood this trigonomy stuff yet..
Hi, Maria, I am Susan, :redface: What matt told you to do is something like this: :blushing:
cosx(cosx-2sinx) =0
cosx=0 OR tanx=1/2
 
Last edited:
hi again

Can you explain it to me a bit more?

I need to understand the whole prosess, because I have to explain it to someone else on thursday.. I need 4 angles..
 
What you basically have is:

a^2 = ab

You can wright this is:

a^2 - ab = 0

a(a - b) = 0

This tells you that either a is 0 or a - b is 0, right? Well try and follow that procedure out with your trig functions.
 
Thanks

I got it right :smile: Thanks a lot
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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