Question #5f32d

2 Answers
Feb 15, 2018

#-cotxcscx#

Explanation:

We have #d/dx1/sinx#

We can apply the quotient rule, that is, #(f/g)'#, where Newton's notation is used and #f# and #g# are functions, is equal to #(f'g-fg')/g^2#.

Here, #f=1# and #g=sinx#. We can input:

#(d/dx(1)*sinx-1*d/dx(sinx))/sin^2x#

We must find #f'# and #g'#.

#d/dx1=0#, so the above equation reduces to:

#(-d/dxsinx)/sin^2x#

Since #d/dxsinx=cosx#, we can input:

#-cosx/sin^2x#

Or:

#-cosx/sinx*1/sinx#

Since #cosx/sinx=cotx# and #1/sinx=cscx#, this becomes:

#-cotxcscx#

Feb 15, 2018

#-cotxcscx#

Explanation:

#"differentiate using the "color(blue)"chain rule"#

#"given "y=f(g(x))" then"#

#dy/dx=f'(g(x)xxg'(x)#

#"here "y=1/sinx=(sinx)^-1#

#rArrdy/dx=-(sinx)^-2xxd/dx(sinx)#

#color(white)(rArrdy/dx)=-cosx(sinx)^-2#

#color(white)(rArrdy/dx)=-cosx/(sin^2x#

#color(white)(rArrdy/dx)=-cosx/sinx xx1/sinx#

#color(white)(rArrdy/dx)=-cotxcscx#