Calculus

[plain kettle]

can someone explain why the cosy becomes cos^2y here?

[arctic wasp]

multiply the top side and the bottom side (of the previous expression) by cos(y)

and voila

u have your answer

[plain kettle]

i thought because the cosy is on the denominator it would look like sinxcosycosx/cosy

[arctic wasp]

?

wdym

[plain kettle]

i just dont know why the answer would be as shown if you're multiplying a fraction on both the numerator and the denominator

or am i overthinking this

[arctic wasp]

prob

if u multiply the top by cos(y) u get

$\cos(y)(\cos(y)\cos(x) + \sin(x)\sin(y)\frac{\sin(x)}{\cos(y)})$

[jolly shard]

Arm

[arctic wasp]

right

using the distributive property u get exactly that numerator

[plain kettle]

oh i see

you're trying to remove the cosy on the denominator of that fraction

thats why you multiply an extra cosy to both the top and the bottom

wait no that doesnt make sense

oh wait it does nvm yeah you use distributive property

tysm!

[arctic wasp]

np