Question

How do you write the expression as the sine, cosine, or tangent of the angle given `(tan25^circ+tan10^circ)/(1-tan25^circtan10^circ)`?

Answer 1

`tan35^@`

Explanation:

Using/knowing the `color(blue)"trigonometric identity"`

`color(red)(bar(ul(|color(white)(2/2)color(black)(tan(x+y)=(tanx+tany)/(1-tanxtany))color(white)(2/2)|)))`

`rArr(tan25^@+tan10^@)/(1-tan25^@tan10^@)`

`=tan(25+10)^@`

`=tan35^@`