Posted by Anonymous on Tuesday, February 21, 2012 at 3:31pm.
Simplify:
sin(xy)cosy+cos(xy)siny
= (sinxcosycosxsiny)cosy+(cosxcosy+sinxsiny)siny
= ???
What do I do next???
Please Help and Thank You

Trigonometry Help  Reiny, Tuesday, February 21, 2012 at 5:08pm
expand it again
= sinx cos^2 y  cosxsinycosy + cosxcosysiny + sinxsin^2 y
= sinx(cos^2 y  sin^2 y)
= sinxcos(2y)

Trigonometry Help  Anonymous, Tuesday, February 21, 2012 at 5:19pm
when I substitue the x's and y's I get different answers.
do I need brackets on (sinxcosycosxsiny) and (cosxcosy+sinxsiny)?
could the next step be: sinxcosycosxsinycosy+cosxcosy+sinxsinysiny without the brackets? or would that be wrong?

correction  Trigonometry Help  Reiny, Tuesday, February 21, 2012 at 6:01pm
found my error
2nd last line should have been
= sinx(cos^2 y + sin^2 y)
= sinx (1)
= sinx

Trigonometry Help  Anonymous, Tuesday, February 21, 2012 at 6:12pm
thank you so much=)
Answer This Question
Related Questions
 Math  Suppose f(x) = sin(pi*cosx) On any interval where the inverse function y...
 Trigo help!  Ok, i've tried this question, and it brings me to no answers. ...
 Trigonometry  Prove that (cosy/1+siny) + (1+siny/cosy) = 2secy
 Math help again  cos(3π/4+x) + sin (3π/4 x) = 0 = cos(3π/4)cosx...
 calc  what is the derivative of sinx cosy = 0 in its simplest form? I got to ...
 Trig (inverse functions)  Problem: tan[arccsc(5/3) + arctan(1/4)] My work: let...
 trig  Okay, I've been getting some of these, but I can't seem to verify this ...
 Math  How do I get (sinx cosy + cosx siny) (cosx cosy + sinx siny) in the form ...
 maths (trigonometry)  please solve these if possible Q1. If sinx +siny=3(cosy...
 calculus help  y=cosxcosysinxsiny/sinxcosy+cosxsiny find dy/dx plz show me ...
More Related Questions