Object doesn't support property or method 'forkJoin'

in app.component.ts

ngAfterViewInit(){
this.weather.getPosition().then(resp=>{
this.weather.currentWeather(resp.coords.longitude,resp.coords.latitude)
.subscribe(
res =>{
console.log(res);
}

  )
  });

}


in Providers

import ‘rxjs/add/observable/forkJoin’;

import ‘rxjs/add/operator/map’;

import ‘rxjs/Rx’;

currentWeather(lon: number, lat: number): Observable<any> {

const currentInfo = this.http.get(http://api.openweathermap.org/data/2.5/weather?lat=${lat}&amp;lon=${lon}&amp;units=metric&amp;APPID=${this.apiKey});

const forecastInfo = this.http.get(http://api.openweathermap.org/data/2.5/forecast/daily?lat=${lat}&amp;lon=${lon}&amp;units=metric&amp;cnt=10&amp;APPID=${this.apiKey});

return Observable.forkJoin([currentInfo, forecastInfo])

.map(responses => {

return .concat(…responses);

});

}


Attaching the image of the Error.

Please Help