# PracticeEvaluate Trig Expressions 1

#### puremath

##### New member
Evaluate each expression given that

f(x) = sin x

g(x) = cos x

h(x) = tan x

k(x) = 2x

A. f(5pi/6 + pi/6)

B. g[k(3pi/4)]

Last edited:

#### MarkFL

##### La Villa Strangiato
Math Helper
A. It looks like $$f$$ is defined to be a function of 1 variable, so treating it like a function of two variables makes no sense.

B. Give this a go...you should be able to show that it is zero.

#### puremath

##### New member
A. It looks like $$f$$ is defined to be a function of 1 variable, so treating it like a function of two variables makes no sense.

B. Give this a go...you should be able to show that it is zero.

I edited A. This looks like composition of functions.

#### MarkFL

##### La Villa Strangiato
Math Helper
Adding the argument, we find it is:

[MATH]f(\pi)=0[/MATH]