High number problem, limit! To find the limit of Tan X / Tan 3x, where x approaches 90 degrees, we need to use the law of lobida But I'll take steps

High number problem, limit! To find the limit of Tan X / Tan 3x, where x approaches 90 degrees, we need to use the law of lobida But I'll take steps

My answer is similar to the one on the second floor. First, I change the whole formula into the form of SiNx and cosx, and take the value of SiNx directly to get - cos3x / cosx. Then I use the law of lobida to get the derivative, and get - 3sin3x / SiNx, and then substitute the value to get 3