# Prove: (tan y + Cot y) sin y cos y = 1

#### Jasonp914

Hi, I need to prove:

(tan y + Cot y) sin y cos y = 1

I've gotten this far and got stuck:

(tany + cos y) sin y cos y changed Cot to reciprical
--------sin y

(sin y tany + cosy) sin y cos y common demonator
--------siny

(sin y tany + cos y) cosy multipyied by sin y

then i could distribute

cos y sin y tan y + cos(sqared) y but how would that equal 1?

Last edited:

#### Nylex

It should help if you plug in

[tex]\tan x = \frac{\sin x}{\cos x}[/itex]

Last edited:

#### GregA

just a suggestion of my own, but try expressing those ratios literally in terms of fractions (ie: sin theta = o/h)...simplify the equation now and see if you notice anything familiar.

#### Jasonp914

o got it thank you!

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving