Find the differentiation of y=cos^-1(ax)? Calculus Differentiating Trigonometric Functions Differentiating Inverse Trigonometric Functions 1 Answer maganbhai P. Apr 27, 2018 y=cos^-1(ax)=>(dy)/(dx)=-1/sqrt(1-(ax)^2)d/(dx)(ax)y=cos−1(ax)⇒dydx=−1√1−(ax)2ddx(ax) (dy)/(dx)=-1/sqrt(1-a^2x^2)xxa=(-a)/sqrt(1-a^2x^2)dydx=−1√1−a2x2×a=−a√1−a2x2 Note: color(red)(d/(dX)(cos^-1X)=-1/sqrt(1-X^2)ddX(cos−1X)=−1√1−X2 Explanation: Here, y=cos^-1(ax)y=cos−1(ax) Let, u=ax=>(du)/(dx)=au=ax⇒dudx=a So, y=cos^-1u=>(dy)/(du)=-1/sqrt(1-u^2)So,y=cos−1u⇒dydu=−1√1−u2 "Using "color(blue)"Chain Rule"Using Chain Rule, color(blue)((dy)/(dx)=(dy)/(du)*(du)/(dx)dydx=dydu⋅dudx :.(dy)/(dx)=-1/sqrt(1-u^2)xxa=(-a)/sqrt(1-u^2),where, u=ax =>(dy)/(dx)=(-a)/sqrt(1-(ax)^2) =>(dy)/(dx)=(-a)/sqrt(1-a^2x^2) Answer link Related questions What is the derivative of f(x)=sin^-1(x) ? What is the derivative of f(x)=cos^-1(x) ? What is the derivative of f(x)=tan^-1(x) ? What is the derivative of f(x)=sec^-1(x) ? What is the derivative of f(x)=csc^-1(x) ? What is the derivative of f(x)=cot^-1(x) ? What is the derivative of f(x)=(cos^-1(x))/x ? What is the derivative of f(x)=tan^-1(e^x) ? What is the derivative of f(x)=cos^-1(x^3) ? What is the derivative of f(x)=ln(sin^-1(x)) ? See all questions in Differentiating Inverse Trigonometric Functions Impact of this question 5378 views around the world You can reuse this answer Creative Commons License