I have a problem with Ionic3

I'm learning how to use Ionic as an example so I'm following a course. I created an intro with 3 slides that in the end I created a "Click" to go to Tabs, with Home and feed, but the Feed stopped working, when I click I will not go any more

Feed.html

See link for more info on   Ionic pages and navigation. - >

    Feed   

<ion-item>
  <ion-avatar item-start>
    <img src="assets/imgs/avatar.png">
  </ion-avatar>
  <h2 class="feed_title">{{ nome_usuario }}</h2>
  <p class="feed_descr">November 5, 1955</p>
</ion-item>

<img src="assets/imgs/advance-card-bttf.png">

<ion-card-content>
  <p>Programar em Ionic é perfeito.</p>
</ion-card-content>

<ion-row>
  <ion-col>
    <button ion-button icon-start clear small>
      <ion-icon name="thumbs-up"></ion-icon>
      <div>12 Likes</div>
    </button>
  </ion-col>
  <ion-col>
    <button ion-button icon-start clear small>
      <ion-icon name="text"></ion-icon>
      <div>4 Comments</div>
    </button>
  </ion-col>
  <ion-col center text-center>
    <ion-note>
      11h ago
    </ion-note>
  </ion-col>
</ion-row>

import { Component } from '@angular/core';

import { AboutPage } from '../about/about';
import { ContactPage } from '../contact/contact';
import { HomePage } from '../home/home';
import { FeedPage } from '../feed/feed';
import { IntroPage } from '../intro/intro';

@Component({
  templateUrl: 'tabs.html'
})
export class TabsPage {

  tab1Root = HomePage;
  tab2Root = FeedPage;
  tab3Root = IntroPage;
  constructor() {

  }
}

different files

<ion-tabs>
  <ion-tab [root]="tab1Root" tabTitle="Home" tabIcon="home"></ion-tab>
  <ion-tab [root]="tab4Root" tabTitle="Feed" tabIcon="ios-paper-outline"></ion-tab>
</ion-tabs>

different files

import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';

/**
 * Generated class for the FeedPage page.
 *
 * See https://ionicframework.com/docs/components/#navigation for more info on
 * Ionic pages and navigation.
 */

@IonicPage()
@Component({
  selector: 'page-feed',
  templateUrl: 'feed.html',
})
export class FeedPage {
  public nome_usuario:string = "Wesley Israel App";
  constructor(public navCtrl: NavController, public navParams: NavParams) {
  }

  public somadoisnumeros(num1:number, num2:number): void{
    alert(num1 + num2);

  }

  ionViewDidLoad() {
    //this.somadoisnumeros(12, 5);
  }

}