#need urgent help in trigonometric identities
26 messages · Page 1 of 1 (latest)
Don't invade others' threads. Create your own.
(y)
Use the difference of squares formula for the right side.
(z)
cos(A)/(csc(A) ± 1) = sin(A)cos(A)/(1 ± sin(A))
So:
2sin(A)/cos(A) = sin(A)cos(A)/(1 - sin(A)) + sin(A)cos(A)/(1 + sin(A))
Divide both sides by sin(A)cos(A).
2/cos(A)^2 = 1/(1 - sin(A)) + 1/(1 + sin(A))
Now just work with the right side.
I dont get number y
I thought we need to solve the left hand side to prove the right hand side
Or is it possible to solve the right hand side in order to prove with the left hand side?
@left shoal
a^2 -b^2 = (a+b)(a-b)
(cos^2x)^2 - (sin^2x)^2 = (cos^2x - sin^2x)(cos^2x+sin^2x)
Notice anything special about either terms?
And anything times 1 is itself
Yes i know
But my question was about whether solving which side would matter or not
In this case the right hand side is being solved
However in the book all example sums are solved using the left hand side so i assumed thats the rule
Does the side matter?
No, as long as you reach the final conclusion
Okay thanks
Idk why your book does that, likely concidence
That clears up my confusion
@glass comet has given 1 rep to @lunar lichen
Or easier to write proofs on one side only
You could theoretically solve on left side by noticing the multiplication by sin^2x + cos^2x but that’s not a very obvious jump
Yup