Trig Test Question: Solving tana^2 = sin2a

[ruthless]

Homework Statement

tana^2 = sin2a

Homework Equations

The Attempt at a Solution

i set tana^a = sec^2a -1
sec^2 -1 = 2sinacosa

didnt know where to go from here <_<

 

[sutupidmath]

do u want to show that tan(a^2)=sin(2a) or what?
and also is the problem like i wrote here or it should be sth like this:(tana)^2=sin(2a)

??

p.s use more parentheses they don't hurt.

 

[ruthless]

do u want to show that tan(a^2)=sin(2a) or what?
and also is the problem like i wrote here or it should be sth like this:(tana)^2=sin(2a)

??

p.s use more parentheses they don't hurt.

its the second way
(tana)^2=sin(2a)
and i need to find values for x
for example pi/4 pi/6 answers won't be like that but yea
its not a proof

 

[jgens]

Alright, if you're aiming for solutions, try rearranging/reexpressing the equation so it satisfies the zero product property.

Hint: reexpress (tan(a))^2 in terms of sine and cosine, and reexpress the sin(2a) in terms of cos(a) and sin(a).

 

[ruthless]

well i did
didnt work
trust me I've been on this for an hour and yeah I've tried to set it equal to zero

 

[jgens]

It should be fairly simple if you're familiar with elementary algebraic operations. You need to show what you're trying if you want help.

 

[ruthless]

well ok
i did
sinx^2/cosx^2 = 2sinxcosx
then brign right hind side to left hand side, at the end it comes out to be
sinx^2 - 2sinxcosx^3 = 0
then sin facotrs and sin x = 0
but I am still left with sinx - 2cos^3x

 

[ruthless]

close SOLVED