private void BtnTan_Click(object sender, EventArgs e)
{
//if there's input call the Third library and perform the tan function
if (CheckForInput(tbResult.Text))
{
//if tan returns true output returned value
if (Trigonometry.DegreesTan(double.Parse(tbResult.Text), out double tan))
{
tbResult.Text = tan.ToString();
isTotal = true;
}
//if tan returns false print error to user
else
{
MessageBox.Show("Invalid input");
}
}
//if there's no input or input is invalid print error to user
else
{
MessageBox.Show("Please enter valid input");
}
}