The task is to prove the trigonometric identity that tan(x1+x2) = (tan(x1) + tan(x2)) / (1 - tan(x1)tan(x2)). This involves using the sum of angles formula for tangent and manipulating the expression to show that the left-hand side is equal to the right-hand side. By simplifying both sides of the equation and showing that they are equal, we can confirm that the identity is correct. **

To prove that tan(x1+x2) = (tan(x1) + tan(x2)) / (1 - tan(x1)tan(x2)) is correct, one would need to use trigonometric identities such as the sum-to-product formula and the tangent addition formula. By manipulating the expressions using these identities, one can show that both sides of the equation are equivalent. It is important to carefully follow the steps of the proof and ensure that each manipulation is mathematically sound in order to confirm the correctness of the statement. **

To show that the equation tan(x1+x2) = (tan(x1) + tan(x2)) / (1 - tan(x1)tan(x2)) is correct, we can start by using the sum formula for tangent, which states that tan(x1+x2) = (tan(x1) + tan(x2)) / (1 - tan(x1)tan(x2)). We can then substitute the values of tan(x1) and tan(x2) into the equation and simplify both sides to see if they are equal. Finally, we can verify the result by checking if both sides of the equation are equal for different values of x1 and x2. **

The calorie expenditure for road cycling and mountain biking can vary based on factors such as intensity, terrain, and duration. Generally, road cycling on flat terrain at a moderate pace can burn around 400-600 calories per hour, while mountain biking on varied terrain with hills and obstacles can burn around 500-800 calories per hour. The higher calorie expenditure in mountain biking is due to the increased effort required to navigate the challenging terrain and obstacles. Overall, mountain biking tends to result in a higher calorie expenditure compared to road cycling. **

Yes, it is possible to distinguish a natural tan from a tanning bed tan. A natural tan tends to be more gradual and even, often developing over time with exposure to the sun. On the other hand, a tanning bed tan can appear more sudden and may have a more uniform color due to the concentrated UV exposure. Additionally, tanning bed tans may have a slightly different tone or hue compared to a natural tan. **

Whether or not you should stop mountain biking depends on your personal circumstances and reasons for considering stopping. If you are experiencing physical pain or injury from mountain biking, it may be wise to take a break and seek medical advice. If you are feeling burnt out or no longer enjoying the activity, it may be beneficial to explore other forms of exercise or outdoor activities. Ultimately, the decision to stop mountain biking should be based on your own well-being and enjoyment. **

Mobile TAN (mTAN) and Smart TAN are both methods of generating one-time passwords for online banking transactions. The main difference between the two is the method of receiving the TAN. With Mobile TAN, the one-time password is sent to the user's mobile phone via SMS. On the other hand, Smart TAN uses a dedicated device, often a small card reader or a smartphone app, to generate the TAN. While Mobile TAN relies on the user's mobile phone and network coverage, Smart TAN requires the use of a separate device, providing an extra layer of security. **

A TAN (Transaction Authentication Number) is a one-time password used to authenticate online transactions. It is typically sent to the user's mobile phone via SMS or generated by a security token. When you receive an SMS with a TAN, it is a security measure to ensure that you are the authorized user making the transaction, as you will need to enter the TAN to complete the transaction. **