How do I prove this:
(cscx/cscx - 1) + (cscx/cscx+1) = 2sec^2x.
Major test tmrw so any help is appreciated.
(cscx/cscx - 1) + (cscx/cscx+1) = 2sec^2x.
Major test tmrw so any help is appreciated.
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I am assuming that the expression is:
cscx/(cscx - 1) + cscx/(cscx + 1) = 2sec²x.
Since csc(x) = 1/sin(x):
csc(x)/(csc(x) - 1) + csc(x)/(csc(x) + 1)
= 1/sin(x)/(1/sin(x) - 1) + 1/sin(x)/(1/sin(x) + 1)
Then, for each fractional expression, multiply the numerator and denominator of sin(x).
1/sin(x)/(1/sin(x) - 1) * sin(x)/sin(x) + 1/sin(x)/(1/sin(x) + 1) * sin(x)/sin(x)
So the expression becomes:
1/(1 - sin(x)) + 1/(1 + sin(x))
Next, by LCD method and expanding (1 + sin(x)(1 - sin(x)):
1/(1 - sin(x)) * (1 + sin(x))/(1 + sin(x)) + 1/(1 + sin(x)) * (1 - sin(x))/(1 - sin(x))
= (1 + sin(x))/((1 + sin(x))(1 - sin(x))) + (1 - sin(x))/((1 + sin(x))(1 - sin(x)))
= (1 + sin(x) + 1 - sin(x))/((1 + sin(x))(1 - sin(x)))
= 2/(1 - sin²(x))
Recall that the Pythagorean identity is:
sin²(x) + cos²(x) = 1
Rearrange the terms:
1 - sin²(x) = cos²(x)
So:
2/cos²(x)
= 2sec²(x) [Noting that 1/cos²(x) = sec²(x)]
= RHS
I hope this helps!
cscx/(cscx - 1) + cscx/(cscx + 1) = 2sec²x.
Since csc(x) = 1/sin(x):
csc(x)/(csc(x) - 1) + csc(x)/(csc(x) + 1)
= 1/sin(x)/(1/sin(x) - 1) + 1/sin(x)/(1/sin(x) + 1)
Then, for each fractional expression, multiply the numerator and denominator of sin(x).
1/sin(x)/(1/sin(x) - 1) * sin(x)/sin(x) + 1/sin(x)/(1/sin(x) + 1) * sin(x)/sin(x)
So the expression becomes:
1/(1 - sin(x)) + 1/(1 + sin(x))
Next, by LCD method and expanding (1 + sin(x)(1 - sin(x)):
1/(1 - sin(x)) * (1 + sin(x))/(1 + sin(x)) + 1/(1 + sin(x)) * (1 - sin(x))/(1 - sin(x))
= (1 + sin(x))/((1 + sin(x))(1 - sin(x))) + (1 - sin(x))/((1 + sin(x))(1 - sin(x)))
= (1 + sin(x) + 1 - sin(x))/((1 + sin(x))(1 - sin(x)))
= 2/(1 - sin²(x))
Recall that the Pythagorean identity is:
sin²(x) + cos²(x) = 1
Rearrange the terms:
1 - sin²(x) = cos²(x)
So:
2/cos²(x)
= 2sec²(x) [Noting that 1/cos²(x) = sec²(x)]
= RHS
I hope this helps!
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I'm assuming
(csc / [csc - 1]) + (csc/[csc + 1]) = csc ([csc + 1] + [csc - 1])/(csc^2 - 1) = 2csc^2/(csc^2 - 1) = 2 / ( 1 - sin^2) = 2/cos^2 = 2 sec^2
csc = 1/sin, sec = 1/cos
(csc / [csc - 1]) + (csc/[csc + 1]) = csc ([csc + 1] + [csc - 1])/(csc^2 - 1) = 2csc^2/(csc^2 - 1) = 2 / ( 1 - sin^2) = 2/cos^2 = 2 sec^2
csc = 1/sin, sec = 1/cos