Englishfor English speakers
frustration
Noun
—
Frustration is the bad feeling of not being able to do what you want to do.
He stood on a chair, but to his frustration, he still could not reach the jar.
—
A thing that frustrates.
function
Noun
—
Something or someone's function is its purpose or its job.
The army sometimes performs a policing function.
—
A function is an organised event.
I met Sylvia at a church function last week.
—
If mathX/math is a function of mathY/math, then mathX/math exists because of or is affected by mathY/math
The speed of the computer is a function of its main processor.
When you see, mathY=f(X)/math, you read it, "mathY/math is a function of mathX/math". Here the value of mathY/math depends on the value assigned to the variable mathX/math.
function
Verb
—
If something is functioning, it is working and is not completely broken.
Her heart stopped, but her brain continued to function.
—
If something functions as mathX/math, it does the job of mathX/math.
In this sentence, "sentence" functions as the subject.