- #1
ZedCar
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Homework Statement
Differentiate with respect to x
y = tan^(-1) x
Homework Equations
The Attempt at a Solution
ANSWER in book:
y = tan^(-1) x
x = tan y
dx/dy = sec^(2) y = (1 + x^2)
dy/dx = 1 / (1 + x^2)
How is it known that sec^(2) y = (1 + x^2)
Does it follow from an identity?