How to smoothly increase the speed of rotation

Questions & Answers
1

Hello Devs!

I want my object to increase rotation speed smoothly from 0 speed to 5 on the z axis, so if someone knows the solution i would be very grateful if you could share it with me!

Here is my code:

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class rotateleft : MonoBehaviour, IEventSystemHandler {

public float speed = 2f;
bool buttonHeld = false;

public void pressed (BaseEventData eventData)
{
	buttonHeld = true;
	GameObject.Find("LeftImage").GetComponent<Animation>().Play("LEFT");
}
public void notpressed(BaseEventData eventData)
{
	buttonHeld = false;
	GameObject.Find("LeftImage").GetComponent<Animation>().Play("LEFT1");

}

public void FixedUpdate()
{
	if (buttonHeld)
	{
		transform.Rotate(Time.smoothDeltaTime, 0, speed * Time.deltaTime);

	} 

		
}

}

2

public float speed = 1f;
public float speed_max = 1f;
public float speed_increaseSpeed = 2f;

private IEnumerator IncreaseSpeed() {
     for(float t = 0; t < 1f; t += Time.deltaTime * speed_increaseSpeed ) {
            speed = Mathf.Lerp(speed, speed_max , t);
           yield return null;
     }
}