Method cos

__test__/theorem.js:425–444

(n)

  	return result.length == 1 ? result[0] : result
  }
  cos(n) {
  	if (n.isComplex) {
  		const a = n.a.toNumber()
  		const b = n.b.toNumber()
  
  		const re = Math.cos(a) * Math.cosh(b)
  		const im = Math.sin(a) * Math.sinh(b)
  
  		return this.complex(re, -im)
  	}
      if (typeof n != 'object' || BigNumber.isBigNumber(n)) {
  		n = BigNumber.isBigNumber(n) == true ? n.toNumber() : n
          n = [n]
      }
  	let result = []
      for (var i = 0; i < n.length; i++) {
      	result.push(Math.cos(n[i]).toFixed(15))
      }
  	return result.length == 1 ? result[0] : result
  }
  cosh(n) {
  	if (n.isComplex) {
  		const a = n.a.toNumber()