How do you solve this? cosθ-tanθcosθ=0

First, lets note that . This leads us with the following problem:



Lets add sin on both sides, and we get:



Now if we divide with sin on both sides we get:



Now we can remember how cot is defined, it is (cos/sin). So we have:



Now take the inverse of cot and we get:


In general we have , the reason we have to add pi times n, is because it is a function that has multiple answers, see the picture:

(-14+3/2b) - (1+8/2b) = -5 -5/2b(-10+b) + (7b-5) = 8b-15(7/2b-3) - (8+6b) = -5/2b-11(5+2b) + (2b+3/2) = 4b+ 13/2