19). 4sin^2x/cos^2x - cos^2x/cos^2x
4(1-cos^2x) - cos^2x. All over cos^2x
4 - 4cos^2x - cos^2x. All over cos^2x
4 - 5cos^2x. All over cos^2x
4/cos^2x - 5
I was given 21 questions for homework and I can't get the last few no matter how hard and how many times I try.
17. Sinx-1/sinx+1 = -cos^2x/(sinx+1)^2
18. Sin^4x + 2sin^2xcos^2x + cos^4x = 1
19. 4/cos^2x - 5 = 4tan^2x - 1
20. Cosx - sinx - cos^3x/Cosx = sin^2 - tanx
21. Sin^2x - 6sinx + 9/sin^2x - 9 = sinx-3/sinx+3
Especially the last three!
5 answers
20). Sin^2x - sin x / cos x
(1-cos^2x)cos x - sin x. All over cos x
Cos x - cos^3x - sin x. All over cos x
(1-cos^2x)cos x - sin x. All over cos x
Cos x - cos^3x - sin x. All over cos x
21). Factor the numerator and the denominator
(Sin x - 3)(sin x - 3) / (sin x - 3)(sin x + 3)
(Sin x - 3)(sin x - 3) / (sin x - 3)(sin x + 3)
17). Multiply numerator and denominator by
Sin x + 1
The numerator ( sin x + 1)(sin x -1) = sin ^2x -1
= -1(1 - sin^2x) = -cos^2x
Sin x + 1
The numerator ( sin x + 1)(sin x -1) = sin ^2x -1
= -1(1 - sin^2x) = -cos^2x
18). Factor perfect square ( sin ^2x + cos^2x)^2
= 1^2=1
= 1^2=1