I am positive that you meant that to type
sin^2x + cos^2x =1
label a right angled triangle having sides a, b, and c
with c as the hypotenuse and angle Ø opposite side a.
LS = sin^2Ø + cos^2Ø
= (a/c)^2 + (b/c)^2
= (a^2/c^2) + (b^2/c^2)
= (a^2 + b^2)/c^2 , but a^2 + b^2 = c^2 by Pythagoras
LS = c^2/c^2
(the choice of variable does not matter, you can call your angle Ø or x or whatever)
the original problem was:
(sin x + cos x)^2 + (sin x - cos x)^2 = 2
In that case you expanded it incorrectly, should have been
=(sin x + cos x)^2 + (sin x - cos x)^2
= sin^2x + 2sinxcosx + cos^2x + sin^2x - 2sinxcosx + cos^2x
= sin^2x+cos^2x + sin^2x + cos^2x
TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...
Math - Prove each identity: a) 1-cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x-1 = sin...
trig - The expression 4 sin x cos x is equivalent to which of the following? (...
Math (Trig) - sorry, another I can't figure out Show that (1-cot^2x)/(tan^2x-1)=...
Math - Solving for Trig Equations - Solve the following equation for 0 less than...
Math - help really needed - Prove each idenity. 1+1/tan^2x=1/sin^2x 1/cosx-cosx=...
Calculus (help Steve plz) - 1) if w = <-8, 15>, find ||w||? 2) which ...
Mathematics - Trigonometric Identities - Prove: sin^2x - sin^4x = cos^2x - cos^...
Mathematics - Trigonometric Identities - Reiny - Mathematics - Trigonometric ...
Math - help really needed - I'm sorry to double post; I don't want to seem ...